Arrhythmias & EP

The extensive surface of the gastrointestinal tract presents an interface between the human body and its environment. Residing within the intestinal lumen, ingested food and various microorganisms are an essential aspect of this relationship. The trillions of microorganisms, primarily commensal bacteria hosted by the human gut, constitute the human gut microbiome.

There is growing evidence that the human gut microbiome plays a role in maintaining normal body function and homeostasis.¹ Research, such as the National Institute of Health Microbiome Project, is helping to show the impact of gut microorganisms and their negative influence on metabolic diseases and chronic inflammatory disorders.^2-5 An imbalance in the microbiota, known as dysbiosis, has been associated with metabolic and cardiovascular diseases (CVD), including hypertension, diabetes mellitus, obesity, and coronary artery disease (CAD). Gut dysbiosis has also been associated with cardiac arrhythmias, including atrial fibrillation (AF) and ventricular arrhythmias (Figure).^6-12

Whether gut dysbiosis is a cause or effect of the human disease process is unclear. While further research is warranted, some evidence of causation has been found. In 2018, Yoshida et al demonstrated an association between patients with CAD who had a significantly lower burden of the gut bacteria species Bacteroides vulgatus and Bacteroides dorei compared to that of patients without CAD. The study found that administration of these Bacteroides species reduced atherosclerotic lesion formation in atherosclerosis-prone mice.¹³ If altering gut microbial composition can affect the disease process, it may indicate a causative role for gut dysbiosis in disease pathogenesis. Furthermore, this finding also suggests agents may be used to alter the gut microbiome and potentially prevent and treat diseases. An altered gut microbiome may serve as an early marker for human disease, aiding in timely diagnosis and institution of disease-modifying treatments.

This review outlines the broad relationship of the pathways and intermediaries that may be involved in mediating the interaction between the gut microbiome and cardiac arrhythmias based on rapidly increasing evidence. A comprehensive search among PubMed and Google Scholar databases was conducted to find articles relevant to the topic.

Potential Intermediaries

Potential pathways for how the gut microbiome and cardiovascular system interact are subjects of active research. However, recent research may point to potential mechanisms of the association between the systems. The gut microbiome may influence human physiology through 3 principal routes: the autonomic nervous system, inflammatory pathways, and metabolic processes.

Autonomic Nervous System

The concept of bidirectional communication between the gut and central nervous system, known as the microbiota-gut-brain axis, is widely accepted.¹⁴ Proposed mediators of this interaction include the vagus nerve, the sympathetic nervous system, and the hypothalamic-pituitary-adrenal axis; cytokines produced by the immune system, tryptophan metabolism, and the production of short-chain fatty acids (SCFAs).^15,16

The gut microbiome appears to have a direct impact on the autonomic nervous system, through which it can influence cardiovascular function. Muller et al described how the gut microbiome modulated gut-extrinsic sympathetic neurons and that the depletion of gut microbiota led to activation of both brainstem sensory nuclei and efferent sympathetic premotor glutamatergic neurons.¹⁶ Meng et al found that systemic injection of the gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) led to significantly increased activity in the paraventricular nucleus, a hypothalamic structure essential to the central autonomic network. Their study demonstrated that systemic TMAO also led to increased left stellate ganglion (LSG) activity, a known contributor to cardiac sympathetic tone.¹²

Inflammatory Pathways

Inflammatory responses are another pathway for the gut microbiome to influence the cardiovascular system. SCFAs are a set of gut microbial metabolites produced in the colon by bacterial fermentation and decomposition of resistant starches and dietary fibers.¹⁷ These metabolites are increasingly recognized for their role in modulating disease processes, including cardiac disease. Aguilar et al found that the progression of atherosclerosis was slowed in apolipoprotein E (Apo-E) knockout mice by a chow diet supplemented with butyrate, a SCFA, suggesting it is an atheroprotective therapeutic agent. Less adhesion and migration of macrophages, reduced inflammation, improved plaque stability, and lowered atherosclerosis progression.¹⁸ Wei et al demonstrated in animal models that direct microinjection of the proinflammatory factors interleukin (IL)-1Β and tumor necrosis factor (TNF)-αdirectly into the subfornical organ increased heart rate, mean blood pressure, and renal sympathetic nerve activity.¹⁹

Metabolic Processes

Serotonin (5-HT), a metabolite of tryptophan, is a neurotransmitter that regulates many bodily functions and plays a significant role in the microbiota-brain gut axis.²⁰ Oral ingestion of the bacterial species Bifidobacterium infantis increased plasma tryptophan in rat models.²¹ Additionally, many other microorganisms, including species of Candida, Streptococcus, Escherichia, and Enterococcus are known to produce 5-HT.²² While a relationship between the gut microbiome and plasma 5-HT has been established, interactions between 5-HT and the cardiovascular system are complex. Research has shown that stimulation of 5-HT_1A receptors produces bradycardic and vasopressor effects, while stimulation of the 5-HT₂ receptor induces vasoconstriction and tachycardia.²³

A high-fiber diet can lower the incidence of hypertension, although the mechanisms are not clear. One potential reason could be alteration in gut bacteria, as a diet high in fiber has been shown to increase the prevalence of acetate-producing bacteria.²⁴

Atherosclerosis

Research investigating the relationship of the gut microbiome with arrhythmias is in its early stages; however, the connection of the gut microbiome and atherosclerosis is more established.²⁵ Contemporary studies have shown various gut microorganisms associated with atherosclerosis.²⁶ Jie et al reported that patients with atherosclerotic cardiovascular disease had increased Enterobacteriaceae loads and oral cavity-associated bacteria with lower levels of butyrate producing bacteria when compared with healthy controls.²⁷ In addition, microbial metabolites such as TMAO appear to promote atherosclerosis by increasing vascular inflammation and platelet reactivity.²⁶ Researchers are investigating the modulation of these associations to help reduce atherosclerotic burden. Kasahara et al found that Roseburia intestinalis could reduce atherosclerotic disease in mice through the production of butyrate.²⁸ Roberts et al established that administration of TMAO inhibitors reduced TMAO levels while reducing thrombus formation without observable toxicity or increased bleeding risk.²⁹

Atrial Arrhythmias

The gut microbiome can also specifically affect cardiac arrhythmogenesis, and multiple studies suggest possible mediators of this interaction. Certain gut microbiome derived metabolites like TMAO may have a role in promoting AF.³⁰ Other gut microbial metabolites like lipopolysaccharides and indoxyl sulfate are implicated in atrial electrical instability.^31,32 Microbe-derived free fatty acids such as palmitic acid and adrenic acid can precipitate arrhythmogenesis. ^33,34 Preponderances of certain gut bacteria like Ruminococcus, Streptococcus, and Enterococcus, as well as reductions of Faecalibacterium, Alistipes, Oscillibacter, and Bilophila have been detected in patients with AF.⁸ Tabata et al found that certain clusters of bacterial groups led by Ruminococcus species seem to show higher prevalence in patients with AF, whereas the genus Enterobacter was significantly lower compared with control subjects. That study also noted that gut microbial composition is affected by diet and antacid use.³⁵ Gut microbiome-derived serotonin may be another mediator for AF, which may be related to the fact that 5-HT₄ receptors are present in atrial tissue.³⁶

Ventricular Arrhythmias

A critical component to the development of malignant ventricular arrhythmias is an imbalance in autonomic tone; in particular, the overactivation of the sympathetic nervous system.³⁷ Animal models have shown that augmentation of the sympathetic nervous system plays an essential role in the subsequent development of ventricular arrhythmias. ³⁸ Several studies have established the LSG as an important component of the cardiac sympathetic nervous system pathway. ^38,39 Ablation of the LSG has been shown to effectively reduce the burden of malignant arrhythmias, further pointing toward the role of excess sympathetic activity.^37,39 Stellate ganglion denervation has become an established method for managing life-threatening ventricular arrhythmias.⁴⁰

Gut metabolites may have significant effects on cardiac sympathetic activity. Meng et al investigated the effect of TMAO on the LSG in animals and its overall effect on the incidence of ventricular arrhythmias under ischemic conditions. To fully explore this interaction, they examined the effect of TMAO on LSG function though 2 mechanisms: local administration of TMAO within the LSG and systemic administration of TMAO leading to activation of the central sympathetic nervous system. In both protocols, left anterior descending coronary artery occlusion was performed after TMAO administration. Injection of TMAO directly into the LSG was found to significantly increase the cardiac sympathetic tone and incidence of ventricular arrhythmias. In the systemic administration control arm, ventricular arrhythmias were also significantly increased.¹²

Increased inflammatory states appear to correlate with an increase in sympathetic tone and ventricular arrhythmias.¹² In an animal study, direct injection of the proinflammatory factor IL-1Β into the LSG not only resulted in increased inflammation, but aggravated cardiac sympathetic remodeling. This led to a decreased effective refractory period and action potential duration, leading to an increased maximal slope of the restitution curve and higher occurrence of ventricular arrhythmias.⁴¹ Shi et al demonstrated that paraventricular nucleus microinjection with TNF-α and IL-1Β also enhanced the cardiac sympathetic afferent reflex, showing that these proinflammatory cytokines not only upregulate the inflammatory response, but can also have excitatory effects that stimulate sympathetic activity and have the potential to be proarrhythmic.^19,42 Local and systemic administration of the gut microbe-derived TMAO increased the expression of IL-1Β and TNF-α, thus implicating the microbiome as a potential mediator of the inflammatory response and as another potential pathway for increased ventricular arrhythmias.¹²

The N-methyl-d-aspartate receptor (NMDAR) is found in multiple organs—including the heart—but more specifically in the conducting system and myocardium.43,44 Research has discovered an upregulation of NMDARs in the setting of cardiac sympathetic hyperinnervation in rat models both with healed myocardial necrotic injury and without. The infusion of their ligand, NMDA, provoked ventricular tachycardia and ventricular fibrillation in rat models with sympathetic hyperinnervation and healed myocardial necrotic injury.⁴⁵ Another study found that NMDAR activation provoked ventricular arrhythmias, but also prolonged repolarization and induced electrical instability.⁴⁶ Proinflammatory markers have been shown to upregulate the expression of NMDARs; more importantly, NMDAR expression has been shown to be significantly increased in the setting of TMAO administration.^12,47,48

5-HT also appears to have a substantial association with ventricular arrhythmias in addition to atrial arrhythmias. el-Mahdy demonstrated in anesthetized rats with acute coronary ligation that systemic doses of 5-HT represented a significant dose-dependent increase in the duration of ventricular tachycardia and ventricular fibrillation, while also increasing the number of ventricular ectopic beats.⁴⁹ Certain gut microorganisms are known to produce 5-HT, including those in the genera Streptococcus, Escherichia, and Enterococcus.²² Additionally, oral ingestion of the Bifidobacterium infantis increased plasma levels of tryptophan in rat models.²¹ The gut microbiome may have significant effects on plasma serotonin levels, and thus have the potential to alter the risk for ventricular arrhythmias.

The deleterious effects of the gut microbiome have been documented. However, it appears to have potential protective effects, and several studies point to the possible mechanisms of this beneficial interaction. Propionate is a SCFA microorganism produced by gut microbial fermentation.⁵⁰ In a rat model study, Zhou et al found that infusion of sodium propionate significantly reduced ventricular arrhythmias during acute myocardial ischemia or burst stimulation, thus confirming cardioprotective effects.^50,51

Proposed mechanisms for reduced susceptibility to ventricular arrhythmias with propionate infusion include parasympathetic activation via the gut-brain axis, anti-inflammatory pathways, and improved cardiac electrophysiology instability.⁵⁰ In addition butyrate has been found to reduce inflammation and myocardial hypertrophy. Jiang et al demonstrated in rats postmyocardial infarction that butyrate promoted expression of anti-inflammatory M2 macrophage markers, decreased expressions of nerve growth factor and norepinephrine, and decreased the density of nerve fibers for growth-associated protein-43 and tyrosine hydroxylase. The cumulative impact of butyrate led to suppression of inflammation and the inhibition of sympathetic neural remodeling, ultimately resulting in improved cardiac function and reduction in ventricular arrhythmias after myocardial infarction.⁵²

Gut bacteria-derived acetate-mediated reduction in cardiac fibrosis may be another mechanism for the effects on ventricular arrhythmias. Cardiac fibrosis and scar are established as the primary substrate for reentrant ventricular arrhythmias seen in various cardiomyopathies.

Future Directions

The microbiome residing in the human gut has a significant impact on cardiac arrhythmias, the details of which remain unknown. A likely bidirectional relationship exists in which the gut microbiome may affect arrhythmogenesis and in turn be affected by cardiac arrhythmias. The mechanisms of action are not well understood, but likely involve the autonomic nervous system, inflammation, and metabolic pathways.

The gut microbiome is a complex collection of heterogenous microorganisms that have dramatic effects on the human body. Additional research is necessary to identify further associations and causations of gut microorganisms with various human body processes, as well as cardiovascular disease. The microbiome has been shown to directly and indirectly influence the development of different disease states, including the cardiovascular system and cardiac arrhythmias. Several pathways have been proposed through which the gut microbiome can potentially affect cardiac arrhythmogenesis. There are likely several mechanisms simultaneously in operation. Understanding the role of human gut microbiome in the genesis of cardiac arrhythmias not only may improve our understanding of arrhythmias, but also may result in novel treatment options. This could potentially lead to the development of therapeutic options and strategies to modulate the gut microbiome to help detect, prevent, and treat cardiac arrhythmias.

The extensive surface of the gastrointestinal tract presents an interface between the human body and its environment. Residing within the intestinal lumen, ingested food and various microorganisms are an essential aspect of this relationship. The trillions of microorganisms, primarily commensal bacteria hosted by the human gut, constitute the human gut microbiome.

There is growing evidence that the human gut microbiome plays a role in maintaining normal body function and homeostasis.¹ Research, such as the National Institute of Health Microbiome Project, is helping to show the impact of gut microorganisms and their negative influence on metabolic diseases and chronic inflammatory disorders.^2-5 An imbalance in the microbiota, known as dysbiosis, has been associated with metabolic and cardiovascular diseases (CVD), including hypertension, diabetes mellitus, obesity, and coronary artery disease (CAD). Gut dysbiosis has also been associated with cardiac arrhythmias, including atrial fibrillation (AF) and ventricular arrhythmias (Figure).^6-12

Whether gut dysbiosis is a cause or effect of the human disease process is unclear. While further research is warranted, some evidence of causation has been found. In 2018, Yoshida et al demonstrated an association between patients with CAD who had a significantly lower burden of the gut bacteria species Bacteroides vulgatus and Bacteroides dorei compared to that of patients without CAD. The study found that administration of these Bacteroides species reduced atherosclerotic lesion formation in atherosclerosis-prone mice.¹³ If altering gut microbial composition can affect the disease process, it may indicate a causative role for gut dysbiosis in disease pathogenesis. Furthermore, this finding also suggests agents may be used to alter the gut microbiome and potentially prevent and treat diseases. An altered gut microbiome may serve as an early marker for human disease, aiding in timely diagnosis and institution of disease-modifying treatments.

This review outlines the broad relationship of the pathways and intermediaries that may be involved in mediating the interaction between the gut microbiome and cardiac arrhythmias based on rapidly increasing evidence. A comprehensive search among PubMed and Google Scholar databases was conducted to find articles relevant to the topic.

Potential Intermediaries

Potential pathways for how the gut microbiome and cardiovascular system interact are subjects of active research. However, recent research may point to potential mechanisms of the association between the systems. The gut microbiome may influence human physiology through 3 principal routes: the autonomic nervous system, inflammatory pathways, and metabolic processes.

Autonomic Nervous System

The concept of bidirectional communication between the gut and central nervous system, known as the microbiota-gut-brain axis, is widely accepted.¹⁴ Proposed mediators of this interaction include the vagus nerve, the sympathetic nervous system, and the hypothalamic-pituitary-adrenal axis; cytokines produced by the immune system, tryptophan metabolism, and the production of short-chain fatty acids (SCFAs).^15,16

The gut microbiome appears to have a direct impact on the autonomic nervous system, through which it can influence cardiovascular function. Muller et al described how the gut microbiome modulated gut-extrinsic sympathetic neurons and that the depletion of gut microbiota led to activation of both brainstem sensory nuclei and efferent sympathetic premotor glutamatergic neurons.¹⁶ Meng et al found that systemic injection of the gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) led to significantly increased activity in the paraventricular nucleus, a hypothalamic structure essential to the central autonomic network. Their study demonstrated that systemic TMAO also led to increased left stellate ganglion (LSG) activity, a known contributor to cardiac sympathetic tone.¹²

Inflammatory Pathways

Inflammatory responses are another pathway for the gut microbiome to influence the cardiovascular system. SCFAs are a set of gut microbial metabolites produced in the colon by bacterial fermentation and decomposition of resistant starches and dietary fibers.¹⁷ These metabolites are increasingly recognized for their role in modulating disease processes, including cardiac disease. Aguilar et al found that the progression of atherosclerosis was slowed in apolipoprotein E (Apo-E) knockout mice by a chow diet supplemented with butyrate, a SCFA, suggesting it is an atheroprotective therapeutic agent. Less adhesion and migration of macrophages, reduced inflammation, improved plaque stability, and lowered atherosclerosis progression.¹⁸ Wei et al demonstrated in animal models that direct microinjection of the proinflammatory factors interleukin (IL)-1Β and tumor necrosis factor (TNF)-αdirectly into the subfornical organ increased heart rate, mean blood pressure, and renal sympathetic nerve activity.¹⁹

Metabolic Processes

Serotonin (5-HT), a metabolite of tryptophan, is a neurotransmitter that regulates many bodily functions and plays a significant role in the microbiota-brain gut axis.²⁰ Oral ingestion of the bacterial species Bifidobacterium infantis increased plasma tryptophan in rat models.²¹ Additionally, many other microorganisms, including species of Candida, Streptococcus, Escherichia, and Enterococcus are known to produce 5-HT.²² While a relationship between the gut microbiome and plasma 5-HT has been established, interactions between 5-HT and the cardiovascular system are complex. Research has shown that stimulation of 5-HT_1A receptors produces bradycardic and vasopressor effects, while stimulation of the 5-HT₂ receptor induces vasoconstriction and tachycardia.²³

A high-fiber diet can lower the incidence of hypertension, although the mechanisms are not clear. One potential reason could be alteration in gut bacteria, as a diet high in fiber has been shown to increase the prevalence of acetate-producing bacteria.²⁴

Atherosclerosis

Research investigating the relationship of the gut microbiome with arrhythmias is in its early stages; however, the connection of the gut microbiome and atherosclerosis is more established.²⁵ Contemporary studies have shown various gut microorganisms associated with atherosclerosis.²⁶ Jie et al reported that patients with atherosclerotic cardiovascular disease had increased Enterobacteriaceae loads and oral cavity-associated bacteria with lower levels of butyrate producing bacteria when compared with healthy controls.²⁷ In addition, microbial metabolites such as TMAO appear to promote atherosclerosis by increasing vascular inflammation and platelet reactivity.²⁶ Researchers are investigating the modulation of these associations to help reduce atherosclerotic burden. Kasahara et al found that Roseburia intestinalis could reduce atherosclerotic disease in mice through the production of butyrate.²⁸ Roberts et al established that administration of TMAO inhibitors reduced TMAO levels while reducing thrombus formation without observable toxicity or increased bleeding risk.²⁹

Atrial Arrhythmias

The gut microbiome can also specifically affect cardiac arrhythmogenesis, and multiple studies suggest possible mediators of this interaction. Certain gut microbiome derived metabolites like TMAO may have a role in promoting AF.³⁰ Other gut microbial metabolites like lipopolysaccharides and indoxyl sulfate are implicated in atrial electrical instability.^31,32 Microbe-derived free fatty acids such as palmitic acid and adrenic acid can precipitate arrhythmogenesis. ^33,34 Preponderances of certain gut bacteria like Ruminococcus, Streptococcus, and Enterococcus, as well as reductions of Faecalibacterium, Alistipes, Oscillibacter, and Bilophila have been detected in patients with AF.⁸ Tabata et al found that certain clusters of bacterial groups led by Ruminococcus species seem to show higher prevalence in patients with AF, whereas the genus Enterobacter was significantly lower compared with control subjects. That study also noted that gut microbial composition is affected by diet and antacid use.³⁵ Gut microbiome-derived serotonin may be another mediator for AF, which may be related to the fact that 5-HT₄ receptors are present in atrial tissue.³⁶

Ventricular Arrhythmias

A critical component to the development of malignant ventricular arrhythmias is an imbalance in autonomic tone; in particular, the overactivation of the sympathetic nervous system.³⁷ Animal models have shown that augmentation of the sympathetic nervous system plays an essential role in the subsequent development of ventricular arrhythmias. ³⁸ Several studies have established the LSG as an important component of the cardiac sympathetic nervous system pathway. ^38,39 Ablation of the LSG has been shown to effectively reduce the burden of malignant arrhythmias, further pointing toward the role of excess sympathetic activity.^37,39 Stellate ganglion denervation has become an established method for managing life-threatening ventricular arrhythmias.⁴⁰

Gut metabolites may have significant effects on cardiac sympathetic activity. Meng et al investigated the effect of TMAO on the LSG in animals and its overall effect on the incidence of ventricular arrhythmias under ischemic conditions. To fully explore this interaction, they examined the effect of TMAO on LSG function though 2 mechanisms: local administration of TMAO within the LSG and systemic administration of TMAO leading to activation of the central sympathetic nervous system. In both protocols, left anterior descending coronary artery occlusion was performed after TMAO administration. Injection of TMAO directly into the LSG was found to significantly increase the cardiac sympathetic tone and incidence of ventricular arrhythmias. In the systemic administration control arm, ventricular arrhythmias were also significantly increased.¹²

Increased inflammatory states appear to correlate with an increase in sympathetic tone and ventricular arrhythmias.¹² In an animal study, direct injection of the proinflammatory factor IL-1Β into the LSG not only resulted in increased inflammation, but aggravated cardiac sympathetic remodeling. This led to a decreased effective refractory period and action potential duration, leading to an increased maximal slope of the restitution curve and higher occurrence of ventricular arrhythmias.⁴¹ Shi et al demonstrated that paraventricular nucleus microinjection with TNF-α and IL-1Β also enhanced the cardiac sympathetic afferent reflex, showing that these proinflammatory cytokines not only upregulate the inflammatory response, but can also have excitatory effects that stimulate sympathetic activity and have the potential to be proarrhythmic.^19,42 Local and systemic administration of the gut microbe-derived TMAO increased the expression of IL-1Β and TNF-α, thus implicating the microbiome as a potential mediator of the inflammatory response and as another potential pathway for increased ventricular arrhythmias.¹²

The N-methyl-d-aspartate receptor (NMDAR) is found in multiple organs—including the heart—but more specifically in the conducting system and myocardium.43,44 Research has discovered an upregulation of NMDARs in the setting of cardiac sympathetic hyperinnervation in rat models both with healed myocardial necrotic injury and without. The infusion of their ligand, NMDA, provoked ventricular tachycardia and ventricular fibrillation in rat models with sympathetic hyperinnervation and healed myocardial necrotic injury.⁴⁵ Another study found that NMDAR activation provoked ventricular arrhythmias, but also prolonged repolarization and induced electrical instability.⁴⁶ Proinflammatory markers have been shown to upregulate the expression of NMDARs; more importantly, NMDAR expression has been shown to be significantly increased in the setting of TMAO administration.^12,47,48

5-HT also appears to have a substantial association with ventricular arrhythmias in addition to atrial arrhythmias. el-Mahdy demonstrated in anesthetized rats with acute coronary ligation that systemic doses of 5-HT represented a significant dose-dependent increase in the duration of ventricular tachycardia and ventricular fibrillation, while also increasing the number of ventricular ectopic beats.⁴⁹ Certain gut microorganisms are known to produce 5-HT, including those in the genera Streptococcus, Escherichia, and Enterococcus.²² Additionally, oral ingestion of the Bifidobacterium infantis increased plasma levels of tryptophan in rat models.²¹ The gut microbiome may have significant effects on plasma serotonin levels, and thus have the potential to alter the risk for ventricular arrhythmias.

The deleterious effects of the gut microbiome have been documented. However, it appears to have potential protective effects, and several studies point to the possible mechanisms of this beneficial interaction. Propionate is a SCFA microorganism produced by gut microbial fermentation.⁵⁰ In a rat model study, Zhou et al found that infusion of sodium propionate significantly reduced ventricular arrhythmias during acute myocardial ischemia or burst stimulation, thus confirming cardioprotective effects.^50,51

Proposed mechanisms for reduced susceptibility to ventricular arrhythmias with propionate infusion include parasympathetic activation via the gut-brain axis, anti-inflammatory pathways, and improved cardiac electrophysiology instability.⁵⁰ In addition butyrate has been found to reduce inflammation and myocardial hypertrophy. Jiang et al demonstrated in rats postmyocardial infarction that butyrate promoted expression of anti-inflammatory M2 macrophage markers, decreased expressions of nerve growth factor and norepinephrine, and decreased the density of nerve fibers for growth-associated protein-43 and tyrosine hydroxylase. The cumulative impact of butyrate led to suppression of inflammation and the inhibition of sympathetic neural remodeling, ultimately resulting in improved cardiac function and reduction in ventricular arrhythmias after myocardial infarction.⁵²

Gut bacteria-derived acetate-mediated reduction in cardiac fibrosis may be another mechanism for the effects on ventricular arrhythmias. Cardiac fibrosis and scar are established as the primary substrate for reentrant ventricular arrhythmias seen in various cardiomyopathies.

Future Directions

The microbiome residing in the human gut has a significant impact on cardiac arrhythmias, the details of which remain unknown. A likely bidirectional relationship exists in which the gut microbiome may affect arrhythmogenesis and in turn be affected by cardiac arrhythmias. The mechanisms of action are not well understood, but likely involve the autonomic nervous system, inflammation, and metabolic pathways.

The gut microbiome is a complex collection of heterogenous microorganisms that have dramatic effects on the human body. Additional research is necessary to identify further associations and causations of gut microorganisms with various human body processes, as well as cardiovascular disease. The microbiome has been shown to directly and indirectly influence the development of different disease states, including the cardiovascular system and cardiac arrhythmias. Several pathways have been proposed through which the gut microbiome can potentially affect cardiac arrhythmogenesis. There are likely several mechanisms simultaneously in operation. Understanding the role of human gut microbiome in the genesis of cardiac arrhythmias not only may improve our understanding of arrhythmias, but also may result in novel treatment options. This could potentially lead to the development of therapeutic options and strategies to modulate the gut microbiome to help detect, prevent, and treat cardiac arrhythmias.

The extensive surface of the gastrointestinal tract presents an interface between the human body and its environment. Residing within the intestinal lumen, ingested food and various microorganisms are an essential aspect of this relationship. The trillions of microorganisms, primarily commensal bacteria hosted by the human gut, constitute the human gut microbiome.

There is growing evidence that the human gut microbiome plays a role in maintaining normal body function and homeostasis.¹ Research, such as the National Institute of Health Microbiome Project, is helping to show the impact of gut microorganisms and their negative influence on metabolic diseases and chronic inflammatory disorders.^2-5 An imbalance in the microbiota, known as dysbiosis, has been associated with metabolic and cardiovascular diseases (CVD), including hypertension, diabetes mellitus, obesity, and coronary artery disease (CAD). Gut dysbiosis has also been associated with cardiac arrhythmias, including atrial fibrillation (AF) and ventricular arrhythmias (Figure).^6-12

Whether gut dysbiosis is a cause or effect of the human disease process is unclear. While further research is warranted, some evidence of causation has been found. In 2018, Yoshida et al demonstrated an association between patients with CAD who had a significantly lower burden of the gut bacteria species Bacteroides vulgatus and Bacteroides dorei compared to that of patients without CAD. The study found that administration of these Bacteroides species reduced atherosclerotic lesion formation in atherosclerosis-prone mice.¹³ If altering gut microbial composition can affect the disease process, it may indicate a causative role for gut dysbiosis in disease pathogenesis. Furthermore, this finding also suggests agents may be used to alter the gut microbiome and potentially prevent and treat diseases. An altered gut microbiome may serve as an early marker for human disease, aiding in timely diagnosis and institution of disease-modifying treatments.

This review outlines the broad relationship of the pathways and intermediaries that may be involved in mediating the interaction between the gut microbiome and cardiac arrhythmias based on rapidly increasing evidence. A comprehensive search among PubMed and Google Scholar databases was conducted to find articles relevant to the topic.

Potential Intermediaries

Potential pathways for how the gut microbiome and cardiovascular system interact are subjects of active research. However, recent research may point to potential mechanisms of the association between the systems. The gut microbiome may influence human physiology through 3 principal routes: the autonomic nervous system, inflammatory pathways, and metabolic processes.

Autonomic Nervous System

The concept of bidirectional communication between the gut and central nervous system, known as the microbiota-gut-brain axis, is widely accepted.¹⁴ Proposed mediators of this interaction include the vagus nerve, the sympathetic nervous system, and the hypothalamic-pituitary-adrenal axis; cytokines produced by the immune system, tryptophan metabolism, and the production of short-chain fatty acids (SCFAs).^15,16

The gut microbiome appears to have a direct impact on the autonomic nervous system, through which it can influence cardiovascular function. Muller et al described how the gut microbiome modulated gut-extrinsic sympathetic neurons and that the depletion of gut microbiota led to activation of both brainstem sensory nuclei and efferent sympathetic premotor glutamatergic neurons.¹⁶ Meng et al found that systemic injection of the gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) led to significantly increased activity in the paraventricular nucleus, a hypothalamic structure essential to the central autonomic network. Their study demonstrated that systemic TMAO also led to increased left stellate ganglion (LSG) activity, a known contributor to cardiac sympathetic tone.¹²

Inflammatory Pathways

Inflammatory responses are another pathway for the gut microbiome to influence the cardiovascular system. SCFAs are a set of gut microbial metabolites produced in the colon by bacterial fermentation and decomposition of resistant starches and dietary fibers.¹⁷ These metabolites are increasingly recognized for their role in modulating disease processes, including cardiac disease. Aguilar et al found that the progression of atherosclerosis was slowed in apolipoprotein E (Apo-E) knockout mice by a chow diet supplemented with butyrate, a SCFA, suggesting it is an atheroprotective therapeutic agent. Less adhesion and migration of macrophages, reduced inflammation, improved plaque stability, and lowered atherosclerosis progression.¹⁸ Wei et al demonstrated in animal models that direct microinjection of the proinflammatory factors interleukin (IL)-1Β and tumor necrosis factor (TNF)-αdirectly into the subfornical organ increased heart rate, mean blood pressure, and renal sympathetic nerve activity.¹⁹

Metabolic Processes

Serotonin (5-HT), a metabolite of tryptophan, is a neurotransmitter that regulates many bodily functions and plays a significant role in the microbiota-brain gut axis.²⁰ Oral ingestion of the bacterial species Bifidobacterium infantis increased plasma tryptophan in rat models.²¹ Additionally, many other microorganisms, including species of Candida, Streptococcus, Escherichia, and Enterococcus are known to produce 5-HT.²² While a relationship between the gut microbiome and plasma 5-HT has been established, interactions between 5-HT and the cardiovascular system are complex. Research has shown that stimulation of 5-HT_1A receptors produces bradycardic and vasopressor effects, while stimulation of the 5-HT₂ receptor induces vasoconstriction and tachycardia.²³

A high-fiber diet can lower the incidence of hypertension, although the mechanisms are not clear. One potential reason could be alteration in gut bacteria, as a diet high in fiber has been shown to increase the prevalence of acetate-producing bacteria.²⁴

Atherosclerosis

Research investigating the relationship of the gut microbiome with arrhythmias is in its early stages; however, the connection of the gut microbiome and atherosclerosis is more established.²⁵ Contemporary studies have shown various gut microorganisms associated with atherosclerosis.²⁶ Jie et al reported that patients with atherosclerotic cardiovascular disease had increased Enterobacteriaceae loads and oral cavity-associated bacteria with lower levels of butyrate producing bacteria when compared with healthy controls.²⁷ In addition, microbial metabolites such as TMAO appear to promote atherosclerosis by increasing vascular inflammation and platelet reactivity.²⁶ Researchers are investigating the modulation of these associations to help reduce atherosclerotic burden. Kasahara et al found that Roseburia intestinalis could reduce atherosclerotic disease in mice through the production of butyrate.²⁸ Roberts et al established that administration of TMAO inhibitors reduced TMAO levels while reducing thrombus formation without observable toxicity or increased bleeding risk.²⁹

Atrial Arrhythmias

The gut microbiome can also specifically affect cardiac arrhythmogenesis, and multiple studies suggest possible mediators of this interaction. Certain gut microbiome derived metabolites like TMAO may have a role in promoting AF.³⁰ Other gut microbial metabolites like lipopolysaccharides and indoxyl sulfate are implicated in atrial electrical instability.^31,32 Microbe-derived free fatty acids such as palmitic acid and adrenic acid can precipitate arrhythmogenesis. ^33,34 Preponderances of certain gut bacteria like Ruminococcus, Streptococcus, and Enterococcus, as well as reductions of Faecalibacterium, Alistipes, Oscillibacter, and Bilophila have been detected in patients with AF.⁸ Tabata et al found that certain clusters of bacterial groups led by Ruminococcus species seem to show higher prevalence in patients with AF, whereas the genus Enterobacter was significantly lower compared with control subjects. That study also noted that gut microbial composition is affected by diet and antacid use.³⁵ Gut microbiome-derived serotonin may be another mediator for AF, which may be related to the fact that 5-HT₄ receptors are present in atrial tissue.³⁶

Ventricular Arrhythmias

A critical component to the development of malignant ventricular arrhythmias is an imbalance in autonomic tone; in particular, the overactivation of the sympathetic nervous system.³⁷ Animal models have shown that augmentation of the sympathetic nervous system plays an essential role in the subsequent development of ventricular arrhythmias. ³⁸ Several studies have established the LSG as an important component of the cardiac sympathetic nervous system pathway. ^38,39 Ablation of the LSG has been shown to effectively reduce the burden of malignant arrhythmias, further pointing toward the role of excess sympathetic activity.^37,39 Stellate ganglion denervation has become an established method for managing life-threatening ventricular arrhythmias.⁴⁰

Gut metabolites may have significant effects on cardiac sympathetic activity. Meng et al investigated the effect of TMAO on the LSG in animals and its overall effect on the incidence of ventricular arrhythmias under ischemic conditions. To fully explore this interaction, they examined the effect of TMAO on LSG function though 2 mechanisms: local administration of TMAO within the LSG and systemic administration of TMAO leading to activation of the central sympathetic nervous system. In both protocols, left anterior descending coronary artery occlusion was performed after TMAO administration. Injection of TMAO directly into the LSG was found to significantly increase the cardiac sympathetic tone and incidence of ventricular arrhythmias. In the systemic administration control arm, ventricular arrhythmias were also significantly increased.¹²

Increased inflammatory states appear to correlate with an increase in sympathetic tone and ventricular arrhythmias.¹² In an animal study, direct injection of the proinflammatory factor IL-1Β into the LSG not only resulted in increased inflammation, but aggravated cardiac sympathetic remodeling. This led to a decreased effective refractory period and action potential duration, leading to an increased maximal slope of the restitution curve and higher occurrence of ventricular arrhythmias.⁴¹ Shi et al demonstrated that paraventricular nucleus microinjection with TNF-α and IL-1Β also enhanced the cardiac sympathetic afferent reflex, showing that these proinflammatory cytokines not only upregulate the inflammatory response, but can also have excitatory effects that stimulate sympathetic activity and have the potential to be proarrhythmic.^19,42 Local and systemic administration of the gut microbe-derived TMAO increased the expression of IL-1Β and TNF-α, thus implicating the microbiome as a potential mediator of the inflammatory response and as another potential pathway for increased ventricular arrhythmias.¹²

The N-methyl-d-aspartate receptor (NMDAR) is found in multiple organs—including the heart—but more specifically in the conducting system and myocardium.43,44 Research has discovered an upregulation of NMDARs in the setting of cardiac sympathetic hyperinnervation in rat models both with healed myocardial necrotic injury and without. The infusion of their ligand, NMDA, provoked ventricular tachycardia and ventricular fibrillation in rat models with sympathetic hyperinnervation and healed myocardial necrotic injury.⁴⁵ Another study found that NMDAR activation provoked ventricular arrhythmias, but also prolonged repolarization and induced electrical instability.⁴⁶ Proinflammatory markers have been shown to upregulate the expression of NMDARs; more importantly, NMDAR expression has been shown to be significantly increased in the setting of TMAO administration.^12,47,48

5-HT also appears to have a substantial association with ventricular arrhythmias in addition to atrial arrhythmias. el-Mahdy demonstrated in anesthetized rats with acute coronary ligation that systemic doses of 5-HT represented a significant dose-dependent increase in the duration of ventricular tachycardia and ventricular fibrillation, while also increasing the number of ventricular ectopic beats.⁴⁹ Certain gut microorganisms are known to produce 5-HT, including those in the genera Streptococcus, Escherichia, and Enterococcus.²² Additionally, oral ingestion of the Bifidobacterium infantis increased plasma levels of tryptophan in rat models.²¹ The gut microbiome may have significant effects on plasma serotonin levels, and thus have the potential to alter the risk for ventricular arrhythmias.

The deleterious effects of the gut microbiome have been documented. However, it appears to have potential protective effects, and several studies point to the possible mechanisms of this beneficial interaction. Propionate is a SCFA microorganism produced by gut microbial fermentation.⁵⁰ In a rat model study, Zhou et al found that infusion of sodium propionate significantly reduced ventricular arrhythmias during acute myocardial ischemia or burst stimulation, thus confirming cardioprotective effects.^50,51

Proposed mechanisms for reduced susceptibility to ventricular arrhythmias with propionate infusion include parasympathetic activation via the gut-brain axis, anti-inflammatory pathways, and improved cardiac electrophysiology instability.⁵⁰ In addition butyrate has been found to reduce inflammation and myocardial hypertrophy. Jiang et al demonstrated in rats postmyocardial infarction that butyrate promoted expression of anti-inflammatory M2 macrophage markers, decreased expressions of nerve growth factor and norepinephrine, and decreased the density of nerve fibers for growth-associated protein-43 and tyrosine hydroxylase. The cumulative impact of butyrate led to suppression of inflammation and the inhibition of sympathetic neural remodeling, ultimately resulting in improved cardiac function and reduction in ventricular arrhythmias after myocardial infarction.⁵²

Gut bacteria-derived acetate-mediated reduction in cardiac fibrosis may be another mechanism for the effects on ventricular arrhythmias. Cardiac fibrosis and scar are established as the primary substrate for reentrant ventricular arrhythmias seen in various cardiomyopathies.

Future Directions

The microbiome residing in the human gut has a significant impact on cardiac arrhythmias, the details of which remain unknown. A likely bidirectional relationship exists in which the gut microbiome may affect arrhythmogenesis and in turn be affected by cardiac arrhythmias. The mechanisms of action are not well understood, but likely involve the autonomic nervous system, inflammation, and metabolic pathways.

The gut microbiome is a complex collection of heterogenous microorganisms that have dramatic effects on the human body. Additional research is necessary to identify further associations and causations of gut microorganisms with various human body processes, as well as cardiovascular disease. The microbiome has been shown to directly and indirectly influence the development of different disease states, including the cardiovascular system and cardiac arrhythmias. Several pathways have been proposed through which the gut microbiome can potentially affect cardiac arrhythmogenesis. There are likely several mechanisms simultaneously in operation. Understanding the role of human gut microbiome in the genesis of cardiac arrhythmias not only may improve our understanding of arrhythmias, but also may result in novel treatment options. This could potentially lead to the development of therapeutic options and strategies to modulate the gut microbiome to help detect, prevent, and treat cardiac arrhythmias.

BOSTON — Patients with COPD who have exacerbations requiring hospitalization should be monitored for cardiac arrhythmias, investigators said.

This recommendation is based on results of a study of medical records showing that among more than 20,000 hospitalizations for patients with COPD without concurrent heart failure (HF), 40% patients had at least 6 minutes of daily atrial fibrillation (AF) burden, and nearly half of these patients had at least an hour of daily AF burden; patients with COPD and concurrent HF had similar daily AF burdens, reported Trent Fischer, MD, MS, senior principal scientist at Medtronic in Minneapolis.

“We can conclude that AF burden increases in the weeks after a hospitalization for COPD if they don’t have a concurrent diagnosis of heart failure. Also, having concurrent heart failure increases the risk of atrial fibrillation and increases the atrial fibrillation burden around the time of COPD hospitalization,” he said in a rapid-fire oral abstract session at the CHEST Annual Meeting.

The findings indicated a need for increased vigilance for AF around the time of a serious COPD exacerbation and may explain at least some of the increased risks for stroke observed in patients who are hospitalized for COPD exacerbations, he said.
 

Retrospective Study

Dr. Fischer and colleagues conducted the study to characterize the AF burden among patients both with and without HF who were hospitalized for acute COPD exacerbation and to determine the temporal relationship between AF and hospitalization.

They drew data from 2007 through 2021 on patients with implantable cardioverter defibrillators, cardiac resynchronization therapy devices, pacemakers, and implantable cardiac monitors, using the Optum de-identified electronic health record dataset linked with Medtronic’s CareLink database to conduct a retrospective analysis.

They looked at admissions for COPD linked to available device diagnostic parameters between 30 days prior to and 60 days after admission for COPD.

They identified a total of 20,056 COPD hospitalizations for patients with concurrent HF and 3877 for those without HF.

Among patients with HF, 43% had a daily AF burden of at least 6 minutes, and 22% had at least 1 hour of irregular rhythms. Among patients without HF, 40% had at least 6 minutes of irregular rhythms daily, and 18% had at least 1 hour.

Among patients with HF, the daily average AF burden increased from a baseline of 158 min/d 30 days before an admission to 170 min/d at admission, returning to baseline by 20 days after hospitalization.

For patients without HF, the AF burden increased from 107 min/d at baseline to 113 min/d during hospitalization and returned to baseline by 20 days after hospitalization.
 

Confounding Factor?

In the Q&A, session moderator Krishna Sundar, MBBS, MD, FCCP, a pulmonary, sleep medicine, and critical care medicine specialist at St. John’s Medical Center in Jackson, Wyoming, said that when patients with HF get admitted for COPD exacerbations, their HF typically worsens and asked Dr. Fischer how he could tell the difference.

“I know there’s a lot of interaction between heart failure and COPD. They’re well-know comorbidities, and the exacerbation of one can bring on worsening of the other. At least with this database, we can’t really tease out any sort of differences,” Dr. Fischer replied.

“I think that a diagnosis of COPD exacerbation is pretty well laid out, but it’s sometimes difficult to separate worsening of heart failure in these patients, and often these patients get treated for both problems. It’s clear that it’s the heart failure patients who are having more atrial fibrillation episodes, which is not surprising, but the question is how much is the COPD exacerbation contributing to the atrial fibrillation?” said Dr. Sundar.

The study was supported by Medtronic. Dr. Fischer is employed by the company. Dr. Sundar reported no relevant financial relationships.



A version of this article appeared on Medscape.com.

BOSTON — Patients with COPD who have exacerbations requiring hospitalization should be monitored for cardiac arrhythmias, investigators said.

This recommendation is based on results of a study of medical records showing that among more than 20,000 hospitalizations for patients with COPD without concurrent heart failure (HF), 40% patients had at least 6 minutes of daily atrial fibrillation (AF) burden, and nearly half of these patients had at least an hour of daily AF burden; patients with COPD and concurrent HF had similar daily AF burdens, reported Trent Fischer, MD, MS, senior principal scientist at Medtronic in Minneapolis.

“We can conclude that AF burden increases in the weeks after a hospitalization for COPD if they don’t have a concurrent diagnosis of heart failure. Also, having concurrent heart failure increases the risk of atrial fibrillation and increases the atrial fibrillation burden around the time of COPD hospitalization,” he said in a rapid-fire oral abstract session at the CHEST Annual Meeting.

The findings indicated a need for increased vigilance for AF around the time of a serious COPD exacerbation and may explain at least some of the increased risks for stroke observed in patients who are hospitalized for COPD exacerbations, he said.
 

Retrospective Study

Dr. Fischer and colleagues conducted the study to characterize the AF burden among patients both with and without HF who were hospitalized for acute COPD exacerbation and to determine the temporal relationship between AF and hospitalization.

They drew data from 2007 through 2021 on patients with implantable cardioverter defibrillators, cardiac resynchronization therapy devices, pacemakers, and implantable cardiac monitors, using the Optum de-identified electronic health record dataset linked with Medtronic’s CareLink database to conduct a retrospective analysis.

They looked at admissions for COPD linked to available device diagnostic parameters between 30 days prior to and 60 days after admission for COPD.

They identified a total of 20,056 COPD hospitalizations for patients with concurrent HF and 3877 for those without HF.

Among patients with HF, 43% had a daily AF burden of at least 6 minutes, and 22% had at least 1 hour of irregular rhythms. Among patients without HF, 40% had at least 6 minutes of irregular rhythms daily, and 18% had at least 1 hour.

Among patients with HF, the daily average AF burden increased from a baseline of 158 min/d 30 days before an admission to 170 min/d at admission, returning to baseline by 20 days after hospitalization.

For patients without HF, the AF burden increased from 107 min/d at baseline to 113 min/d during hospitalization and returned to baseline by 20 days after hospitalization.
 

Confounding Factor?

In the Q&A, session moderator Krishna Sundar, MBBS, MD, FCCP, a pulmonary, sleep medicine, and critical care medicine specialist at St. John’s Medical Center in Jackson, Wyoming, said that when patients with HF get admitted for COPD exacerbations, their HF typically worsens and asked Dr. Fischer how he could tell the difference.

“I know there’s a lot of interaction between heart failure and COPD. They’re well-know comorbidities, and the exacerbation of one can bring on worsening of the other. At least with this database, we can’t really tease out any sort of differences,” Dr. Fischer replied.

“I think that a diagnosis of COPD exacerbation is pretty well laid out, but it’s sometimes difficult to separate worsening of heart failure in these patients, and often these patients get treated for both problems. It’s clear that it’s the heart failure patients who are having more atrial fibrillation episodes, which is not surprising, but the question is how much is the COPD exacerbation contributing to the atrial fibrillation?” said Dr. Sundar.

The study was supported by Medtronic. Dr. Fischer is employed by the company. Dr. Sundar reported no relevant financial relationships.



A version of this article appeared on Medscape.com.

BOSTON — Patients with COPD who have exacerbations requiring hospitalization should be monitored for cardiac arrhythmias, investigators said.

This recommendation is based on results of a study of medical records showing that among more than 20,000 hospitalizations for patients with COPD without concurrent heart failure (HF), 40% patients had at least 6 minutes of daily atrial fibrillation (AF) burden, and nearly half of these patients had at least an hour of daily AF burden; patients with COPD and concurrent HF had similar daily AF burdens, reported Trent Fischer, MD, MS, senior principal scientist at Medtronic in Minneapolis.

“We can conclude that AF burden increases in the weeks after a hospitalization for COPD if they don’t have a concurrent diagnosis of heart failure. Also, having concurrent heart failure increases the risk of atrial fibrillation and increases the atrial fibrillation burden around the time of COPD hospitalization,” he said in a rapid-fire oral abstract session at the CHEST Annual Meeting.

The findings indicated a need for increased vigilance for AF around the time of a serious COPD exacerbation and may explain at least some of the increased risks for stroke observed in patients who are hospitalized for COPD exacerbations, he said.
 

Retrospective Study

Dr. Fischer and colleagues conducted the study to characterize the AF burden among patients both with and without HF who were hospitalized for acute COPD exacerbation and to determine the temporal relationship between AF and hospitalization.

They drew data from 2007 through 2021 on patients with implantable cardioverter defibrillators, cardiac resynchronization therapy devices, pacemakers, and implantable cardiac monitors, using the Optum de-identified electronic health record dataset linked with Medtronic’s CareLink database to conduct a retrospective analysis.

They looked at admissions for COPD linked to available device diagnostic parameters between 30 days prior to and 60 days after admission for COPD.

They identified a total of 20,056 COPD hospitalizations for patients with concurrent HF and 3877 for those without HF.

Among patients with HF, 43% had a daily AF burden of at least 6 minutes, and 22% had at least 1 hour of irregular rhythms. Among patients without HF, 40% had at least 6 minutes of irregular rhythms daily, and 18% had at least 1 hour.

Among patients with HF, the daily average AF burden increased from a baseline of 158 min/d 30 days before an admission to 170 min/d at admission, returning to baseline by 20 days after hospitalization.

For patients without HF, the AF burden increased from 107 min/d at baseline to 113 min/d during hospitalization and returned to baseline by 20 days after hospitalization.
 

Confounding Factor?

In the Q&A, session moderator Krishna Sundar, MBBS, MD, FCCP, a pulmonary, sleep medicine, and critical care medicine specialist at St. John’s Medical Center in Jackson, Wyoming, said that when patients with HF get admitted for COPD exacerbations, their HF typically worsens and asked Dr. Fischer how he could tell the difference.

“I know there’s a lot of interaction between heart failure and COPD. They’re well-know comorbidities, and the exacerbation of one can bring on worsening of the other. At least with this database, we can’t really tease out any sort of differences,” Dr. Fischer replied.

“I think that a diagnosis of COPD exacerbation is pretty well laid out, but it’s sometimes difficult to separate worsening of heart failure in these patients, and often these patients get treated for both problems. It’s clear that it’s the heart failure patients who are having more atrial fibrillation episodes, which is not surprising, but the question is how much is the COPD exacerbation contributing to the atrial fibrillation?” said Dr. Sundar.

The study was supported by Medtronic. Dr. Fischer is employed by the company. Dr. Sundar reported no relevant financial relationships.



A version of this article appeared on Medscape.com.

The incidence of atrial fibrillation (AF) is on the rise, and recent joint guidelines from the American College of Cardiology and American Heart Association (ACC/AHA) stress the role of primary care clinicians in prevention and management.

One in three White and one in five Black Americans will develop AF in their lifetime, and the projected number of individuals diagnosed with AF in the United States is expected to double by 2050.

Cardiologists who spoke to Medscape Medical News said primary care clinicians can help control AF by focusing on diabetes and hypertension, along with lifestyle factors such as diet, exercise, and alcohol intake.

“It’s not just a rhythm abnormality, but a complex disease that needs to be addressed in a multidisciplinary, holistic way,” said Jose Joglar, MD, a professor in the Department of Internal Medicine at the UT Southwestern Medical Center in Dallas and lead author of the guidelines.

Joglar said primary care clinicians can play an important role in counseling on lifestyle changes for patients with the most common etiologies such as poorly controlled hypertension, diabetes, and obesity.
 

The Primary Care Physicians ABCs: Risk Factors and Comorbidities

The three pillars of the new ACC/AHA guidelines include: Stroke risk assessment and management; optimize the patient’s risks; and symptom management.

“As a primary care physician or as a cardiologist, I often think that if I do these things, I’m going to help with a lot of conditions, not just atrial fibrillation,” said Manesh Patel, MD, chief of the Divisions of Cardiology and Clinical Pharmacology at the Duke University School of Medicine in Durham, North Carolina.

Lifestyle choices such as sleeping habits can play a big part in AF outcomes. Although the guidelines specifically address obstructive sleep apnea as a risk factor, he said more data are needed on the effect of sleep hygiene — getting 8 hours of sleep a night — a goal few people attain.

“What we do know is people that can routinely try to go to sleep and sleep with some regularity seem to have less cardiovascular risk,” Patel said.

Although existing data are limited, literature reviews have found evidence that sleep disruptions, sleep duration, circadian rhythm, and insomnia are associated with heart disease, independent of obstructive sleep apnea.

Use of alcohol should also be discussed with patients, as many are unaware of the effects of the drug on cardiovascular disease, said Joglar, who is also the program director of the Clinical Cardiac Electrophysiology Fellowship program at the UT Southwestern Medical Center.

“Doctors can inform the patient that this is not a judgment call but simple medical fact,” he said.

Joglar also said many physicians need to become educated on a common misconception.

“Every time a patient develops palpitations or atrial fibrillation, the first thing every patient tells me is, I quit drinking coffee,” Joglar said.

However, as the guidelines point out, the link between caffeine and AF is uncertain at best.
 

Preventing AF

A newer class of drugs may help clinicians manage comorbidities that contribute to AF, such as hypertension, sleep apnea, and obesity, said John Mandrola, MD, an electrophysiologist in Louisville, Kentucky, who hosts This Week in Cardiology on Medscape.

Although originally approved for treatment of diabetes, sodium-glucose cotransporter-2 inhibitors are also approved for management of heart failure. Mandrola started prescribing these drugs 2 years ago for patients, given the links of both conditions with AF.

“I think the next frontier for us in cardiology and AF management will be the GLP-1 agonists,” Mandrola said. He hasn’t started prescribing these drugs for his patients yet but said they will likely play a role in the management of patients with AF with the common constellation of comorbidities such as obesity, hypertension, and sleep apnea. 

“The GLP-1 agonists have a really good chance of competing with AF ablation for rhythm control over the long term,” he said.
 

Decisions, Decisions: Stroke Risk Scoring Systems

The risk for stroke varies widely among patients with AF, so primary care clinicians can pick among several scoring systems to estimate the risk for stroke and guide the decision on whether to initiate anticoagulation therapy.

The ACC/AHA guidelines do not state a preference for a particular instrument. The Congestive heart failure, Hypertension, Age, Diabetes mellitus, Stroke, Vascular disease, Sex (CHA2DS2-VASc) score is the most widely used and validated instrument, Joglar said. He usually recommends anticoagulation if the CHA2DS2-VASc score is > 2, dependent on individual patient factors.

“If you have a CHA2DS2-VASc score of 1, and you only had one episode of AF for a few hours a year ago, then your risk of stroke is not as high as somebody who has a score of 1 but has more frequent or persistent AF,” Joglar said.

None of the systems is perfect at predicting risk for stroke, so clinicians should discuss options with patients.

“The real message is, are you talking about the risk of stroke and systemic embolism to your patient, so that the patient understands that risk?” he said.

Patel also said measuring creatine clearance can be analogous to using an instrument like CHA2DS2-VASc.

“I often think about renal disease as a very good risk marker and something that does elevate your risk,” he said.
 

Which Anticoagulant?

Although the ACC/AHA guidelines still recommend warfarin for patients with AF with mechanical heart valves or moderate to severe rheumatic fever, direct oral anticoagulants (DOACs) are the first-line therapy for all other patients with AF.

In terms of which DOACs to use, the differences are subtle, according to Patel.

“I don’t know that they’re that different from each other,” he said. “All of the new drugs are better than warfarin by far.”

Patel pointed out that dabigatran at 150 mg is the only DOAC shown to reduce the incidence of ischemic stroke. For patients with renal dysfunction, he has a slight preference for a 15-mg dose of rivaroxaban.

Mandrola said he mainly prescribes apixaban and rivaroxaban, the latter of which requires only once a day dosing.

“We stopped using dabigatran because 10% of people get gastrointestinal upset,” he said.

Although studies suggest aspirin is less effective than either warfarin or DOACs for the prevention of stroke, Joglar said he still sees patients who come to him after being prescribed low-dose aspirin from primary care clinicians.

“We made it very clear that it should not be recommended just for mitigating stroke risk in atrial fibrillation,” Joglar said. “You could use it if the patient has another indication, such as a prior heart attack.”
 

Does My Patient Have to Be in Normal Sinus Rhythm?

The new guidelines present evidence maintaining sinus rhythm should be favored over controlling heart rate for managing AF.

“We’ve focused on rhythm control as a better strategy, especially catheter ablation, which seems to be particularly effective in parallel to lifestyle interventions and management of comorbidities,” Joglar said. Rhythm control is of particular benefit for patients with AF triggered by heart failure. Control of rhythm in these patients has been shown to improve multiple outcomes such as ejection fraction, symptoms, and survival.

Patel said as a patient’s symptoms increase, the more likely a clinician will be able to control sinus rhythm. Some patients do not notice their arrhythmia, but others feel dizzy or have chest pain.

“The less symptomatic the patient is, the more likely they’re going to tolerate it, especially if they’re older, and it’s hard to get them into sinus rhythm,” Patel said.
 

When to Refer for Catheter Ablation?

The new guidelines upgraded the recommendation for catheter ablation to class I (strong recommendation) for patients with symptomatic AF in whom anti-arrhythmic therapy is unsuccessful, not tolerated, or contraindicated; patients with symptomatic paroxysmal AF (typically younger patients with few comorbidities); and patients with symptomatic or clinically significant atrial flutter. The previous iteration recommended trying drug therapy first.

Multiple randomized clinical trials have demonstrated the effectiveness of catheter ablation.

“In somebody who is younger, with a healthy heart, the 1-year success rate of the procedure might be about 70%,” Joglar said. While 70% of patients receiving a catheter have no AF episodes in the following year, Joglar said 20%-25% of those who do have recurrences will experience fewer or shorter episodes.

Conversations about rate vs rhythm control and whether to pursue catheter ablation often come down to preference, Patel said. He would tend to intervene earlier using ablation in patients with heart failure or those experiencing symptoms of AF who cannot be controlled with a heart rate < 100 beats/min.

But he said he prefers using medication for rate control in many of his patients who are older, have chronic AF, and do not have heart failure.

Mandrola takes a more conservative approach, reserving catheter ablation for patients in whom risk factor management and anti-arrhythmic drugs have not been successful.

“In my hospital, it’s done for patients who have symptomatic AF that’s really impacting their quality of life,” he said. But for those with fewer symptoms, his advice is to provide education, reassurance, and time because AF can resolve on its own.
 

What About Data From Implantables and Wearables?

The guidelines provide an algorithm for when to treat non-symptomatic atrial high-rate episodes detected by a cardiovascular implantable electronic device such as a pacemaker or defibrillator. Episodes less than 5 minutes can be ignored, while treatment could be considered for those with episodes lasting 5 minutes up to 24 hours with a CHA2DS2-VASc score ≥ 3, or lasting longer than 24 hours with a CHA2DS2-VASc score ≥ 2.

But whether anticoagulation improves outcomes is unclear.

“That is a $64,000 question,” Mandrola said. “I would bet every day I get a notification in the electronic health record that says Mr. Smith had 2 hours of AFib 2 weeks ago.”

He also hears from patients who report their Apple Watch has detected an episode of AF.

Mandrola cited evidence from two recent studies of patients who had an atrial high-rate episode longer than 6 minutes detected by implantable devices. The NOAH-AFNET 6 trial randomized patients over 65 years with one or more risk factors for stroke to receive a DOAC or placebo, while the ARTESIA trial used similar inclusion criteria to assign patients to receive either DOAC or aspirin. Both studies reported modest reductions in stroke that were outweighed by a higher incidence of major bleeding in the group receiving anticoagulation.

Shared decision-making should play a role in deciding how aggressively to treat episodes of AF detected by implantable or wearable devices.

He said some patients fear having a stroke, while others are adamantly opposed to taking an anticoagulant.

For patients who present with a documented episode of AF but who otherwise have no symptoms, Patel said clinicians should consider risk for stroke and frequency and duration of episodes.

“One way clinicians should be thinking about it is, the more risk factors they have, the lower burden of AF I need to treat,” Patel said. Even for patients who are having only short episodes of AF, he has a low threshold for recommending an anticoagulation drug if the patient’s CHA2DS2-VASc score is high.

Patel reported research grants from Bayer, Novartis, Idorsia, NHLBI, and Janssen Pharmaceuticals and served as a consultant on the advisory boards of Bayer, Janssen Pharmaceuticals, and Esperion Therapeutics. 

Joglar and Mandrola had no disclosures. 

A version of this article appeared on Medscape.com.

The incidence of atrial fibrillation (AF) is on the rise, and recent joint guidelines from the American College of Cardiology and American Heart Association (ACC/AHA) stress the role of primary care clinicians in prevention and management.

One in three White and one in five Black Americans will develop AF in their lifetime, and the projected number of individuals diagnosed with AF in the United States is expected to double by 2050.

Cardiologists who spoke to Medscape Medical News said primary care clinicians can help control AF by focusing on diabetes and hypertension, along with lifestyle factors such as diet, exercise, and alcohol intake.

“It’s not just a rhythm abnormality, but a complex disease that needs to be addressed in a multidisciplinary, holistic way,” said Jose Joglar, MD, a professor in the Department of Internal Medicine at the UT Southwestern Medical Center in Dallas and lead author of the guidelines.

Joglar said primary care clinicians can play an important role in counseling on lifestyle changes for patients with the most common etiologies such as poorly controlled hypertension, diabetes, and obesity.
 

The Primary Care Physicians ABCs: Risk Factors and Comorbidities

The three pillars of the new ACC/AHA guidelines include: Stroke risk assessment and management; optimize the patient’s risks; and symptom management.

“As a primary care physician or as a cardiologist, I often think that if I do these things, I’m going to help with a lot of conditions, not just atrial fibrillation,” said Manesh Patel, MD, chief of the Divisions of Cardiology and Clinical Pharmacology at the Duke University School of Medicine in Durham, North Carolina.

Lifestyle choices such as sleeping habits can play a big part in AF outcomes. Although the guidelines specifically address obstructive sleep apnea as a risk factor, he said more data are needed on the effect of sleep hygiene — getting 8 hours of sleep a night — a goal few people attain.

“What we do know is people that can routinely try to go to sleep and sleep with some regularity seem to have less cardiovascular risk,” Patel said.

Although existing data are limited, literature reviews have found evidence that sleep disruptions, sleep duration, circadian rhythm, and insomnia are associated with heart disease, independent of obstructive sleep apnea.

Use of alcohol should also be discussed with patients, as many are unaware of the effects of the drug on cardiovascular disease, said Joglar, who is also the program director of the Clinical Cardiac Electrophysiology Fellowship program at the UT Southwestern Medical Center.

“Doctors can inform the patient that this is not a judgment call but simple medical fact,” he said.

Joglar also said many physicians need to become educated on a common misconception.

“Every time a patient develops palpitations or atrial fibrillation, the first thing every patient tells me is, I quit drinking coffee,” Joglar said.

However, as the guidelines point out, the link between caffeine and AF is uncertain at best.
 

Preventing AF

A newer class of drugs may help clinicians manage comorbidities that contribute to AF, such as hypertension, sleep apnea, and obesity, said John Mandrola, MD, an electrophysiologist in Louisville, Kentucky, who hosts This Week in Cardiology on Medscape.

Although originally approved for treatment of diabetes, sodium-glucose cotransporter-2 inhibitors are also approved for management of heart failure. Mandrola started prescribing these drugs 2 years ago for patients, given the links of both conditions with AF.

“I think the next frontier for us in cardiology and AF management will be the GLP-1 agonists,” Mandrola said. He hasn’t started prescribing these drugs for his patients yet but said they will likely play a role in the management of patients with AF with the common constellation of comorbidities such as obesity, hypertension, and sleep apnea. 

“The GLP-1 agonists have a really good chance of competing with AF ablation for rhythm control over the long term,” he said.
 

Decisions, Decisions: Stroke Risk Scoring Systems

The risk for stroke varies widely among patients with AF, so primary care clinicians can pick among several scoring systems to estimate the risk for stroke and guide the decision on whether to initiate anticoagulation therapy.

The ACC/AHA guidelines do not state a preference for a particular instrument. The Congestive heart failure, Hypertension, Age, Diabetes mellitus, Stroke, Vascular disease, Sex (CHA2DS2-VASc) score is the most widely used and validated instrument, Joglar said. He usually recommends anticoagulation if the CHA2DS2-VASc score is > 2, dependent on individual patient factors.

“If you have a CHA2DS2-VASc score of 1, and you only had one episode of AF for a few hours a year ago, then your risk of stroke is not as high as somebody who has a score of 1 but has more frequent or persistent AF,” Joglar said.

None of the systems is perfect at predicting risk for stroke, so clinicians should discuss options with patients.

“The real message is, are you talking about the risk of stroke and systemic embolism to your patient, so that the patient understands that risk?” he said.

Patel also said measuring creatine clearance can be analogous to using an instrument like CHA2DS2-VASc.

“I often think about renal disease as a very good risk marker and something that does elevate your risk,” he said.
 

Which Anticoagulant?

Although the ACC/AHA guidelines still recommend warfarin for patients with AF with mechanical heart valves or moderate to severe rheumatic fever, direct oral anticoagulants (DOACs) are the first-line therapy for all other patients with AF.

In terms of which DOACs to use, the differences are subtle, according to Patel.

“I don’t know that they’re that different from each other,” he said. “All of the new drugs are better than warfarin by far.”

Patel pointed out that dabigatran at 150 mg is the only DOAC shown to reduce the incidence of ischemic stroke. For patients with renal dysfunction, he has a slight preference for a 15-mg dose of rivaroxaban.

Mandrola said he mainly prescribes apixaban and rivaroxaban, the latter of which requires only once a day dosing.

“We stopped using dabigatran because 10% of people get gastrointestinal upset,” he said.

Although studies suggest aspirin is less effective than either warfarin or DOACs for the prevention of stroke, Joglar said he still sees patients who come to him after being prescribed low-dose aspirin from primary care clinicians.

“We made it very clear that it should not be recommended just for mitigating stroke risk in atrial fibrillation,” Joglar said. “You could use it if the patient has another indication, such as a prior heart attack.”
 

Does My Patient Have to Be in Normal Sinus Rhythm?

The new guidelines present evidence maintaining sinus rhythm should be favored over controlling heart rate for managing AF.

“We’ve focused on rhythm control as a better strategy, especially catheter ablation, which seems to be particularly effective in parallel to lifestyle interventions and management of comorbidities,” Joglar said. Rhythm control is of particular benefit for patients with AF triggered by heart failure. Control of rhythm in these patients has been shown to improve multiple outcomes such as ejection fraction, symptoms, and survival.

Patel said as a patient’s symptoms increase, the more likely a clinician will be able to control sinus rhythm. Some patients do not notice their arrhythmia, but others feel dizzy or have chest pain.

“The less symptomatic the patient is, the more likely they’re going to tolerate it, especially if they’re older, and it’s hard to get them into sinus rhythm,” Patel said.
 

When to Refer for Catheter Ablation?

The new guidelines upgraded the recommendation for catheter ablation to class I (strong recommendation) for patients with symptomatic AF in whom anti-arrhythmic therapy is unsuccessful, not tolerated, or contraindicated; patients with symptomatic paroxysmal AF (typically younger patients with few comorbidities); and patients with symptomatic or clinically significant atrial flutter. The previous iteration recommended trying drug therapy first.

Multiple randomized clinical trials have demonstrated the effectiveness of catheter ablation.

“In somebody who is younger, with a healthy heart, the 1-year success rate of the procedure might be about 70%,” Joglar said. While 70% of patients receiving a catheter have no AF episodes in the following year, Joglar said 20%-25% of those who do have recurrences will experience fewer or shorter episodes.

Conversations about rate vs rhythm control and whether to pursue catheter ablation often come down to preference, Patel said. He would tend to intervene earlier using ablation in patients with heart failure or those experiencing symptoms of AF who cannot be controlled with a heart rate < 100 beats/min.

But he said he prefers using medication for rate control in many of his patients who are older, have chronic AF, and do not have heart failure.

Mandrola takes a more conservative approach, reserving catheter ablation for patients in whom risk factor management and anti-arrhythmic drugs have not been successful.

“In my hospital, it’s done for patients who have symptomatic AF that’s really impacting their quality of life,” he said. But for those with fewer symptoms, his advice is to provide education, reassurance, and time because AF can resolve on its own.
 

What About Data From Implantables and Wearables?

The guidelines provide an algorithm for when to treat non-symptomatic atrial high-rate episodes detected by a cardiovascular implantable electronic device such as a pacemaker or defibrillator. Episodes less than 5 minutes can be ignored, while treatment could be considered for those with episodes lasting 5 minutes up to 24 hours with a CHA2DS2-VASc score ≥ 3, or lasting longer than 24 hours with a CHA2DS2-VASc score ≥ 2.

But whether anticoagulation improves outcomes is unclear.

“That is a $64,000 question,” Mandrola said. “I would bet every day I get a notification in the electronic health record that says Mr. Smith had 2 hours of AFib 2 weeks ago.”

He also hears from patients who report their Apple Watch has detected an episode of AF.

Mandrola cited evidence from two recent studies of patients who had an atrial high-rate episode longer than 6 minutes detected by implantable devices. The NOAH-AFNET 6 trial randomized patients over 65 years with one or more risk factors for stroke to receive a DOAC or placebo, while the ARTESIA trial used similar inclusion criteria to assign patients to receive either DOAC or aspirin. Both studies reported modest reductions in stroke that were outweighed by a higher incidence of major bleeding in the group receiving anticoagulation.

Shared decision-making should play a role in deciding how aggressively to treat episodes of AF detected by implantable or wearable devices.

He said some patients fear having a stroke, while others are adamantly opposed to taking an anticoagulant.

For patients who present with a documented episode of AF but who otherwise have no symptoms, Patel said clinicians should consider risk for stroke and frequency and duration of episodes.

“One way clinicians should be thinking about it is, the more risk factors they have, the lower burden of AF I need to treat,” Patel said. Even for patients who are having only short episodes of AF, he has a low threshold for recommending an anticoagulation drug if the patient’s CHA2DS2-VASc score is high.

Patel reported research grants from Bayer, Novartis, Idorsia, NHLBI, and Janssen Pharmaceuticals and served as a consultant on the advisory boards of Bayer, Janssen Pharmaceuticals, and Esperion Therapeutics. 

Joglar and Mandrola had no disclosures. 

A version of this article appeared on Medscape.com.

The incidence of atrial fibrillation (AF) is on the rise, and recent joint guidelines from the American College of Cardiology and American Heart Association (ACC/AHA) stress the role of primary care clinicians in prevention and management.

One in three White and one in five Black Americans will develop AF in their lifetime, and the projected number of individuals diagnosed with AF in the United States is expected to double by 2050.

Cardiologists who spoke to Medscape Medical News said primary care clinicians can help control AF by focusing on diabetes and hypertension, along with lifestyle factors such as diet, exercise, and alcohol intake.

“It’s not just a rhythm abnormality, but a complex disease that needs to be addressed in a multidisciplinary, holistic way,” said Jose Joglar, MD, a professor in the Department of Internal Medicine at the UT Southwestern Medical Center in Dallas and lead author of the guidelines.

Joglar said primary care clinicians can play an important role in counseling on lifestyle changes for patients with the most common etiologies such as poorly controlled hypertension, diabetes, and obesity.
 

The Primary Care Physicians ABCs: Risk Factors and Comorbidities

The three pillars of the new ACC/AHA guidelines include: Stroke risk assessment and management; optimize the patient’s risks; and symptom management.

“As a primary care physician or as a cardiologist, I often think that if I do these things, I’m going to help with a lot of conditions, not just atrial fibrillation,” said Manesh Patel, MD, chief of the Divisions of Cardiology and Clinical Pharmacology at the Duke University School of Medicine in Durham, North Carolina.

Lifestyle choices such as sleeping habits can play a big part in AF outcomes. Although the guidelines specifically address obstructive sleep apnea as a risk factor, he said more data are needed on the effect of sleep hygiene — getting 8 hours of sleep a night — a goal few people attain.

“What we do know is people that can routinely try to go to sleep and sleep with some regularity seem to have less cardiovascular risk,” Patel said.

Although existing data are limited, literature reviews have found evidence that sleep disruptions, sleep duration, circadian rhythm, and insomnia are associated with heart disease, independent of obstructive sleep apnea.

Use of alcohol should also be discussed with patients, as many are unaware of the effects of the drug on cardiovascular disease, said Joglar, who is also the program director of the Clinical Cardiac Electrophysiology Fellowship program at the UT Southwestern Medical Center.

“Doctors can inform the patient that this is not a judgment call but simple medical fact,” he said.

Joglar also said many physicians need to become educated on a common misconception.

“Every time a patient develops palpitations or atrial fibrillation, the first thing every patient tells me is, I quit drinking coffee,” Joglar said.

However, as the guidelines point out, the link between caffeine and AF is uncertain at best.
 

Preventing AF

A newer class of drugs may help clinicians manage comorbidities that contribute to AF, such as hypertension, sleep apnea, and obesity, said John Mandrola, MD, an electrophysiologist in Louisville, Kentucky, who hosts This Week in Cardiology on Medscape.

Although originally approved for treatment of diabetes, sodium-glucose cotransporter-2 inhibitors are also approved for management of heart failure. Mandrola started prescribing these drugs 2 years ago for patients, given the links of both conditions with AF.

“I think the next frontier for us in cardiology and AF management will be the GLP-1 agonists,” Mandrola said. He hasn’t started prescribing these drugs for his patients yet but said they will likely play a role in the management of patients with AF with the common constellation of comorbidities such as obesity, hypertension, and sleep apnea. 

“The GLP-1 agonists have a really good chance of competing with AF ablation for rhythm control over the long term,” he said.
 

Decisions, Decisions: Stroke Risk Scoring Systems

The risk for stroke varies widely among patients with AF, so primary care clinicians can pick among several scoring systems to estimate the risk for stroke and guide the decision on whether to initiate anticoagulation therapy.

The ACC/AHA guidelines do not state a preference for a particular instrument. The Congestive heart failure, Hypertension, Age, Diabetes mellitus, Stroke, Vascular disease, Sex (CHA2DS2-VASc) score is the most widely used and validated instrument, Joglar said. He usually recommends anticoagulation if the CHA2DS2-VASc score is > 2, dependent on individual patient factors.

“If you have a CHA2DS2-VASc score of 1, and you only had one episode of AF for a few hours a year ago, then your risk of stroke is not as high as somebody who has a score of 1 but has more frequent or persistent AF,” Joglar said.

None of the systems is perfect at predicting risk for stroke, so clinicians should discuss options with patients.

“The real message is, are you talking about the risk of stroke and systemic embolism to your patient, so that the patient understands that risk?” he said.

Patel also said measuring creatine clearance can be analogous to using an instrument like CHA2DS2-VASc.

“I often think about renal disease as a very good risk marker and something that does elevate your risk,” he said.
 

Which Anticoagulant?

Although the ACC/AHA guidelines still recommend warfarin for patients with AF with mechanical heart valves or moderate to severe rheumatic fever, direct oral anticoagulants (DOACs) are the first-line therapy for all other patients with AF.

In terms of which DOACs to use, the differences are subtle, according to Patel.

“I don’t know that they’re that different from each other,” he said. “All of the new drugs are better than warfarin by far.”

Patel pointed out that dabigatran at 150 mg is the only DOAC shown to reduce the incidence of ischemic stroke. For patients with renal dysfunction, he has a slight preference for a 15-mg dose of rivaroxaban.

Mandrola said he mainly prescribes apixaban and rivaroxaban, the latter of which requires only once a day dosing.

“We stopped using dabigatran because 10% of people get gastrointestinal upset,” he said.

Although studies suggest aspirin is less effective than either warfarin or DOACs for the prevention of stroke, Joglar said he still sees patients who come to him after being prescribed low-dose aspirin from primary care clinicians.

“We made it very clear that it should not be recommended just for mitigating stroke risk in atrial fibrillation,” Joglar said. “You could use it if the patient has another indication, such as a prior heart attack.”
 

Does My Patient Have to Be in Normal Sinus Rhythm?

The new guidelines present evidence maintaining sinus rhythm should be favored over controlling heart rate for managing AF.

“We’ve focused on rhythm control as a better strategy, especially catheter ablation, which seems to be particularly effective in parallel to lifestyle interventions and management of comorbidities,” Joglar said. Rhythm control is of particular benefit for patients with AF triggered by heart failure. Control of rhythm in these patients has been shown to improve multiple outcomes such as ejection fraction, symptoms, and survival.

Patel said as a patient’s symptoms increase, the more likely a clinician will be able to control sinus rhythm. Some patients do not notice their arrhythmia, but others feel dizzy or have chest pain.

“The less symptomatic the patient is, the more likely they’re going to tolerate it, especially if they’re older, and it’s hard to get them into sinus rhythm,” Patel said.
 

When to Refer for Catheter Ablation?

The new guidelines upgraded the recommendation for catheter ablation to class I (strong recommendation) for patients with symptomatic AF in whom anti-arrhythmic therapy is unsuccessful, not tolerated, or contraindicated; patients with symptomatic paroxysmal AF (typically younger patients with few comorbidities); and patients with symptomatic or clinically significant atrial flutter. The previous iteration recommended trying drug therapy first.

Multiple randomized clinical trials have demonstrated the effectiveness of catheter ablation.

“In somebody who is younger, with a healthy heart, the 1-year success rate of the procedure might be about 70%,” Joglar said. While 70% of patients receiving a catheter have no AF episodes in the following year, Joglar said 20%-25% of those who do have recurrences will experience fewer or shorter episodes.

Conversations about rate vs rhythm control and whether to pursue catheter ablation often come down to preference, Patel said. He would tend to intervene earlier using ablation in patients with heart failure or those experiencing symptoms of AF who cannot be controlled with a heart rate < 100 beats/min.

But he said he prefers using medication for rate control in many of his patients who are older, have chronic AF, and do not have heart failure.

Mandrola takes a more conservative approach, reserving catheter ablation for patients in whom risk factor management and anti-arrhythmic drugs have not been successful.

“In my hospital, it’s done for patients who have symptomatic AF that’s really impacting their quality of life,” he said. But for those with fewer symptoms, his advice is to provide education, reassurance, and time because AF can resolve on its own.
 

What About Data From Implantables and Wearables?

The guidelines provide an algorithm for when to treat non-symptomatic atrial high-rate episodes detected by a cardiovascular implantable electronic device such as a pacemaker or defibrillator. Episodes less than 5 minutes can be ignored, while treatment could be considered for those with episodes lasting 5 minutes up to 24 hours with a CHA2DS2-VASc score ≥ 3, or lasting longer than 24 hours with a CHA2DS2-VASc score ≥ 2.

But whether anticoagulation improves outcomes is unclear.

“That is a $64,000 question,” Mandrola said. “I would bet every day I get a notification in the electronic health record that says Mr. Smith had 2 hours of AFib 2 weeks ago.”

He also hears from patients who report their Apple Watch has detected an episode of AF.

Mandrola cited evidence from two recent studies of patients who had an atrial high-rate episode longer than 6 minutes detected by implantable devices. The NOAH-AFNET 6 trial randomized patients over 65 years with one or more risk factors for stroke to receive a DOAC or placebo, while the ARTESIA trial used similar inclusion criteria to assign patients to receive either DOAC or aspirin. Both studies reported modest reductions in stroke that were outweighed by a higher incidence of major bleeding in the group receiving anticoagulation.

Shared decision-making should play a role in deciding how aggressively to treat episodes of AF detected by implantable or wearable devices.

He said some patients fear having a stroke, while others are adamantly opposed to taking an anticoagulant.

For patients who present with a documented episode of AF but who otherwise have no symptoms, Patel said clinicians should consider risk for stroke and frequency and duration of episodes.

“One way clinicians should be thinking about it is, the more risk factors they have, the lower burden of AF I need to treat,” Patel said. Even for patients who are having only short episodes of AF, he has a low threshold for recommending an anticoagulation drug if the patient’s CHA2DS2-VASc score is high.

Patel reported research grants from Bayer, Novartis, Idorsia, NHLBI, and Janssen Pharmaceuticals and served as a consultant on the advisory boards of Bayer, Janssen Pharmaceuticals, and Esperion Therapeutics. 

Joglar and Mandrola had no disclosures. 

A version of this article appeared on Medscape.com.

LONDON — Potassium supplementation does not alter the risk for postoperative atrial fibrillation in patients who have undergone cardiac surgery, contrary to expectations and popular clinical practice, new trial results demonstrate.

“The widespread practice of giving patients potassium after bypass heart surgery even though their blood levels are within the normal range can be abandoned,” said Benjamin O’Brien, MD, PhD, director of the Clinic for Cardioanesthesiology and Intensive Care Medicine at Charité Hospital in Berlin, Germany.

Results from the randomized TIGHT-K trial that assessed two levels of potassium supplementation were presented at the annual congress of the European Society of Cardiology.

In the tight-control group, supplementation was provided to maintain high-normal levels of potassium (> 4.5 mEq/L). In the relaxed-control group, supplementation was provided only when potassium levels fell below the low-normal threshold (< 3.6 mEq/L). 
 

Trial Upending Popular Practice

The multinational trial involved 23 centers in Germany and the United Kingdom. All 1690 participants enrolled were scheduled to undergo a coronary artery bypass graft procedure, but Dr. O’Brien said he considers the results of TIGHT-K to be broadly applicable.

“There is no physiological basis to expect a different result in patients undergoing different types of cardiac surgery,” he said.

The primary endpoint was clinically and electrocardiography confirmed new-onset atrial fibrillation that occurred in the 5 days after the bypass procedure.

For the primary atrial fibrillation endpoint, event rates were similar in the tight-control and the relaxed-control groups (26.2% vs 27.8%); the 1.7% difference did not approach statistical significance (P = .44). The difference in dysrhythmias other than atrial fibrillation, although numerically lower in the tight-control group, was also not significant (19.1% vs 21.1%; P = .26).

There were no significant differences in several secondary endpoints, including length of hospital stay and in-patient mortality, but cost, a prespecified secondary endpoint, was approximately $120 lower per patient in the relaxed-control group than in the tight-control group (P < .001).
 

Lowering Cost Across Cardiac Surgeries

During the 5-day follow-up, median potassium levels were higher in the tight-control group. Levels in both groups fell gradually, but essentially in parallel, over the study period, so median potassium levels were always higher in the tight-control group than in the relaxed-control group. At the end of the observation period, mean potassium levels were 4.34 mEq/L in the tight-control group and 4.08 mEq/L in the relaxed-control group.

Prior to the development of atrial fibrillation, participants in the tight-control group received a medium of seven potassium administrations (range, 4-12), whereas those in the relaxed-control group received a medium of zero.

There were no significant differences in episodes in any subgroup evaluated, including those divided by age, sex, baseline left ventricular ejection fraction, and the absence or presence of beta blockers or loop diuretics. A per-protocol analysis also failed to show any advantage for tight potassium control.

Atrial fibrillation occurs in about one third of patients after bypass surgery, as it does after many types of cardiac surgery. Institutions often have strategies in place to reduce the risk after cardiac surgery, and potassium supplementation is one of the most common, despite the lack of supportive evidence, Dr. O’Brien said.
 

Narrow Window for Optimal Potassium Levels

The difference in potassium levels between the tight-control group and the relaxed-control group were modest in this study, said Subodh Verma, MD, a cardiac surgeon at St Michael’s Hospital and professor at the University of Toronto, Ontario, Canada.

However, this is unavoidable and central to the question being posed, Dr. O’Brien pointed out. Because of the risks for both hypokalemia and hyperkalemia, the window for safe supplementation is short. Current practice is to achieve high-normal levels to reduce atrial fibrillation, but TIGHT-K demonstrates this has no benefit.

The conclusion of TIGHT-K is appropriate, said Faiez Zannad, MD, PhD, professor of therapeutics in the Division of Cardiology at the University of Lorraine in Nancy, France, who praised the design and conduct of the study.

He acknowledged an unmet need for effective methods to reduce the risk for atrial fibrillation after cardiac surgery, but the ESC invited discussant said it is now necessary to look at other strategies. Several are under current evaluation, such as supplementary magnesium and the use of sodium-glucose transporter-2 inhibitors.

Although Dr. Zannad encouraged more studies of methods to reduce atrial fibrillation risk after cardiac surgery, he said that TIGHT-K has answered the question of whether potassium supplementation is beneficial.

Potassium supplementation should no longer be offered, he said, which will “reduce healthcare costs and decrease patient risk from an unnecessary intervention.”

A version of this article first appeared on Medscape.com.

LONDON — Potassium supplementation does not alter the risk for postoperative atrial fibrillation in patients who have undergone cardiac surgery, contrary to expectations and popular clinical practice, new trial results demonstrate.

“The widespread practice of giving patients potassium after bypass heart surgery even though their blood levels are within the normal range can be abandoned,” said Benjamin O’Brien, MD, PhD, director of the Clinic for Cardioanesthesiology and Intensive Care Medicine at Charité Hospital in Berlin, Germany.

Results from the randomized TIGHT-K trial that assessed two levels of potassium supplementation were presented at the annual congress of the European Society of Cardiology.

In the tight-control group, supplementation was provided to maintain high-normal levels of potassium (> 4.5 mEq/L). In the relaxed-control group, supplementation was provided only when potassium levels fell below the low-normal threshold (< 3.6 mEq/L). 
 

Trial Upending Popular Practice

The multinational trial involved 23 centers in Germany and the United Kingdom. All 1690 participants enrolled were scheduled to undergo a coronary artery bypass graft procedure, but Dr. O’Brien said he considers the results of TIGHT-K to be broadly applicable.

“There is no physiological basis to expect a different result in patients undergoing different types of cardiac surgery,” he said.

The primary endpoint was clinically and electrocardiography confirmed new-onset atrial fibrillation that occurred in the 5 days after the bypass procedure.

For the primary atrial fibrillation endpoint, event rates were similar in the tight-control and the relaxed-control groups (26.2% vs 27.8%); the 1.7% difference did not approach statistical significance (P = .44). The difference in dysrhythmias other than atrial fibrillation, although numerically lower in the tight-control group, was also not significant (19.1% vs 21.1%; P = .26).

There were no significant differences in several secondary endpoints, including length of hospital stay and in-patient mortality, but cost, a prespecified secondary endpoint, was approximately $120 lower per patient in the relaxed-control group than in the tight-control group (P < .001).
 

Lowering Cost Across Cardiac Surgeries

During the 5-day follow-up, median potassium levels were higher in the tight-control group. Levels in both groups fell gradually, but essentially in parallel, over the study period, so median potassium levels were always higher in the tight-control group than in the relaxed-control group. At the end of the observation period, mean potassium levels were 4.34 mEq/L in the tight-control group and 4.08 mEq/L in the relaxed-control group.

Prior to the development of atrial fibrillation, participants in the tight-control group received a medium of seven potassium administrations (range, 4-12), whereas those in the relaxed-control group received a medium of zero.

There were no significant differences in episodes in any subgroup evaluated, including those divided by age, sex, baseline left ventricular ejection fraction, and the absence or presence of beta blockers or loop diuretics. A per-protocol analysis also failed to show any advantage for tight potassium control.

Atrial fibrillation occurs in about one third of patients after bypass surgery, as it does after many types of cardiac surgery. Institutions often have strategies in place to reduce the risk after cardiac surgery, and potassium supplementation is one of the most common, despite the lack of supportive evidence, Dr. O’Brien said.
 

Narrow Window for Optimal Potassium Levels

The difference in potassium levels between the tight-control group and the relaxed-control group were modest in this study, said Subodh Verma, MD, a cardiac surgeon at St Michael’s Hospital and professor at the University of Toronto, Ontario, Canada.

However, this is unavoidable and central to the question being posed, Dr. O’Brien pointed out. Because of the risks for both hypokalemia and hyperkalemia, the window for safe supplementation is short. Current practice is to achieve high-normal levels to reduce atrial fibrillation, but TIGHT-K demonstrates this has no benefit.

The conclusion of TIGHT-K is appropriate, said Faiez Zannad, MD, PhD, professor of therapeutics in the Division of Cardiology at the University of Lorraine in Nancy, France, who praised the design and conduct of the study.

He acknowledged an unmet need for effective methods to reduce the risk for atrial fibrillation after cardiac surgery, but the ESC invited discussant said it is now necessary to look at other strategies. Several are under current evaluation, such as supplementary magnesium and the use of sodium-glucose transporter-2 inhibitors.

Although Dr. Zannad encouraged more studies of methods to reduce atrial fibrillation risk after cardiac surgery, he said that TIGHT-K has answered the question of whether potassium supplementation is beneficial.

Potassium supplementation should no longer be offered, he said, which will “reduce healthcare costs and decrease patient risk from an unnecessary intervention.”

A version of this article first appeared on Medscape.com.

LONDON — Potassium supplementation does not alter the risk for postoperative atrial fibrillation in patients who have undergone cardiac surgery, contrary to expectations and popular clinical practice, new trial results demonstrate.

“The widespread practice of giving patients potassium after bypass heart surgery even though their blood levels are within the normal range can be abandoned,” said Benjamin O’Brien, MD, PhD, director of the Clinic for Cardioanesthesiology and Intensive Care Medicine at Charité Hospital in Berlin, Germany.

Results from the randomized TIGHT-K trial that assessed two levels of potassium supplementation were presented at the annual congress of the European Society of Cardiology.

In the tight-control group, supplementation was provided to maintain high-normal levels of potassium (> 4.5 mEq/L). In the relaxed-control group, supplementation was provided only when potassium levels fell below the low-normal threshold (< 3.6 mEq/L). 
 

Trial Upending Popular Practice

The multinational trial involved 23 centers in Germany and the United Kingdom. All 1690 participants enrolled were scheduled to undergo a coronary artery bypass graft procedure, but Dr. O’Brien said he considers the results of TIGHT-K to be broadly applicable.

“There is no physiological basis to expect a different result in patients undergoing different types of cardiac surgery,” he said.

The primary endpoint was clinically and electrocardiography confirmed new-onset atrial fibrillation that occurred in the 5 days after the bypass procedure.

For the primary atrial fibrillation endpoint, event rates were similar in the tight-control and the relaxed-control groups (26.2% vs 27.8%); the 1.7% difference did not approach statistical significance (P = .44). The difference in dysrhythmias other than atrial fibrillation, although numerically lower in the tight-control group, was also not significant (19.1% vs 21.1%; P = .26).

There were no significant differences in several secondary endpoints, including length of hospital stay and in-patient mortality, but cost, a prespecified secondary endpoint, was approximately $120 lower per patient in the relaxed-control group than in the tight-control group (P < .001).
 

Lowering Cost Across Cardiac Surgeries

During the 5-day follow-up, median potassium levels were higher in the tight-control group. Levels in both groups fell gradually, but essentially in parallel, over the study period, so median potassium levels were always higher in the tight-control group than in the relaxed-control group. At the end of the observation period, mean potassium levels were 4.34 mEq/L in the tight-control group and 4.08 mEq/L in the relaxed-control group.

Prior to the development of atrial fibrillation, participants in the tight-control group received a medium of seven potassium administrations (range, 4-12), whereas those in the relaxed-control group received a medium of zero.

There were no significant differences in episodes in any subgroup evaluated, including those divided by age, sex, baseline left ventricular ejection fraction, and the absence or presence of beta blockers or loop diuretics. A per-protocol analysis also failed to show any advantage for tight potassium control.

Atrial fibrillation occurs in about one third of patients after bypass surgery, as it does after many types of cardiac surgery. Institutions often have strategies in place to reduce the risk after cardiac surgery, and potassium supplementation is one of the most common, despite the lack of supportive evidence, Dr. O’Brien said.
 

Narrow Window for Optimal Potassium Levels

The difference in potassium levels between the tight-control group and the relaxed-control group were modest in this study, said Subodh Verma, MD, a cardiac surgeon at St Michael’s Hospital and professor at the University of Toronto, Ontario, Canada.

However, this is unavoidable and central to the question being posed, Dr. O’Brien pointed out. Because of the risks for both hypokalemia and hyperkalemia, the window for safe supplementation is short. Current practice is to achieve high-normal levels to reduce atrial fibrillation, but TIGHT-K demonstrates this has no benefit.

The conclusion of TIGHT-K is appropriate, said Faiez Zannad, MD, PhD, professor of therapeutics in the Division of Cardiology at the University of Lorraine in Nancy, France, who praised the design and conduct of the study.

He acknowledged an unmet need for effective methods to reduce the risk for atrial fibrillation after cardiac surgery, but the ESC invited discussant said it is now necessary to look at other strategies. Several are under current evaluation, such as supplementary magnesium and the use of sodium-glucose transporter-2 inhibitors.

Although Dr. Zannad encouraged more studies of methods to reduce atrial fibrillation risk after cardiac surgery, he said that TIGHT-K has answered the question of whether potassium supplementation is beneficial.

Potassium supplementation should no longer be offered, he said, which will “reduce healthcare costs and decrease patient risk from an unnecessary intervention.”

A version of this article first appeared on Medscape.com.

TOPLINE: 

Patients with both rheumatoid arthritis (RA) and atrial fibrillation (AF) have a higher risk for ischemic stroke than those with only AF. They are also less likely to receive oral anticoagulant treatment, which may contribute to this increased stroke risk.

METHODOLOGY:

• Researchers conducted a registry-based retrospective cohort study using the Norwegian Cardio-Rheuma Register to evaluate the risk for ischemic stroke following the diagnosis of AF in patients with or without RA.
• They included 163,595 patients with newly diagnosed AF between 2010 and 2017, of whom 2750 had RA. Patients had to be diagnosed with RA before the diagnosis of AF.
• They also assessed whether patients with RA were less likely to receive oral anticoagulants for stroke prevention within 3 months of AF diagnosis than those without RA.
• The median follow-up time was 2.5 years for patients with RA and 3.0 years for those without RA.
• The primary endpoint was ischemic stroke, which was identified through hospital admissions and visits.

TAKEAWAY:

• At 5 years, patients with both RA and AF showed a higher cumulative incidence of ischemic stroke than those with only AF (7.3% vs 5.0%).
• Among patients with AF, the risk of having a stroke was 25% higher in those with RA than in those without RA (adjusted hazard ratio, 1.25; 95% CI, 1.05-1.50).
• Patients with RA were also less likely to receive treatment with oral anticoagulants than those without RA, driven by concerns over potential interactions with RA medications, bleeding risk, or other factors (adjusted odds ratio, 0.88; 95% CI, 0.80-0.97). 

IN PRACTICE:

“Our study prompts preventive measures such as meticulous cardiovascular risk factor control among patients with RA and AF and raises the question whether the presence of RA should be taken into account when considering OAC [oral anticoagulant] treatment for AF patients,” the authors wrote.

SOURCE:

This study was led by Anne M. Kerola, MD, PhD, Helsinki University Hospital and University of Helsinki in Finland. It was published online in Rheumatology.

LIMITATIONS: 

This study lacked data on smoking, blood pressure measurements, alcohol use, and obesity, which may have affected the comprehensiveness of the findings. The study population was limited to Norway and may not be generalizable to other populations.

DISCLOSURES:

This study was supported by the Olav Thon Foundation, the Research Council of Norway, and the Foundation for Research in Rheumatology. Some authors received speaker fees, participated in advisory boards, served as consultants, or had other ties with some pharmaceutical companies and institutions.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE: 

Patients with both rheumatoid arthritis (RA) and atrial fibrillation (AF) have a higher risk for ischemic stroke than those with only AF. They are also less likely to receive oral anticoagulant treatment, which may contribute to this increased stroke risk.

METHODOLOGY:

• Researchers conducted a registry-based retrospective cohort study using the Norwegian Cardio-Rheuma Register to evaluate the risk for ischemic stroke following the diagnosis of AF in patients with or without RA.
• They included 163,595 patients with newly diagnosed AF between 2010 and 2017, of whom 2750 had RA. Patients had to be diagnosed with RA before the diagnosis of AF.
• They also assessed whether patients with RA were less likely to receive oral anticoagulants for stroke prevention within 3 months of AF diagnosis than those without RA.
• The median follow-up time was 2.5 years for patients with RA and 3.0 years for those without RA.
• The primary endpoint was ischemic stroke, which was identified through hospital admissions and visits.

TAKEAWAY:

• At 5 years, patients with both RA and AF showed a higher cumulative incidence of ischemic stroke than those with only AF (7.3% vs 5.0%).
• Among patients with AF, the risk of having a stroke was 25% higher in those with RA than in those without RA (adjusted hazard ratio, 1.25; 95% CI, 1.05-1.50).
• Patients with RA were also less likely to receive treatment with oral anticoagulants than those without RA, driven by concerns over potential interactions with RA medications, bleeding risk, or other factors (adjusted odds ratio, 0.88; 95% CI, 0.80-0.97). 

IN PRACTICE:

“Our study prompts preventive measures such as meticulous cardiovascular risk factor control among patients with RA and AF and raises the question whether the presence of RA should be taken into account when considering OAC [oral anticoagulant] treatment for AF patients,” the authors wrote.

SOURCE:

This study was led by Anne M. Kerola, MD, PhD, Helsinki University Hospital and University of Helsinki in Finland. It was published online in Rheumatology.

LIMITATIONS: 

This study lacked data on smoking, blood pressure measurements, alcohol use, and obesity, which may have affected the comprehensiveness of the findings. The study population was limited to Norway and may not be generalizable to other populations.

DISCLOSURES:

This study was supported by the Olav Thon Foundation, the Research Council of Norway, and the Foundation for Research in Rheumatology. Some authors received speaker fees, participated in advisory boards, served as consultants, or had other ties with some pharmaceutical companies and institutions.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE: 

Patients with both rheumatoid arthritis (RA) and atrial fibrillation (AF) have a higher risk for ischemic stroke than those with only AF. They are also less likely to receive oral anticoagulant treatment, which may contribute to this increased stroke risk.

METHODOLOGY:

• Researchers conducted a registry-based retrospective cohort study using the Norwegian Cardio-Rheuma Register to evaluate the risk for ischemic stroke following the diagnosis of AF in patients with or without RA.
• They included 163,595 patients with newly diagnosed AF between 2010 and 2017, of whom 2750 had RA. Patients had to be diagnosed with RA before the diagnosis of AF.
• They also assessed whether patients with RA were less likely to receive oral anticoagulants for stroke prevention within 3 months of AF diagnosis than those without RA.
• The median follow-up time was 2.5 years for patients with RA and 3.0 years for those without RA.
• The primary endpoint was ischemic stroke, which was identified through hospital admissions and visits.

TAKEAWAY:

• At 5 years, patients with both RA and AF showed a higher cumulative incidence of ischemic stroke than those with only AF (7.3% vs 5.0%).
• Among patients with AF, the risk of having a stroke was 25% higher in those with RA than in those without RA (adjusted hazard ratio, 1.25; 95% CI, 1.05-1.50).
• Patients with RA were also less likely to receive treatment with oral anticoagulants than those without RA, driven by concerns over potential interactions with RA medications, bleeding risk, or other factors (adjusted odds ratio, 0.88; 95% CI, 0.80-0.97). 

IN PRACTICE:

“Our study prompts preventive measures such as meticulous cardiovascular risk factor control among patients with RA and AF and raises the question whether the presence of RA should be taken into account when considering OAC [oral anticoagulant] treatment for AF patients,” the authors wrote.

SOURCE:

This study was led by Anne M. Kerola, MD, PhD, Helsinki University Hospital and University of Helsinki in Finland. It was published online in Rheumatology.

LIMITATIONS: 

This study lacked data on smoking, blood pressure measurements, alcohol use, and obesity, which may have affected the comprehensiveness of the findings. The study population was limited to Norway and may not be generalizable to other populations.

DISCLOSURES:

This study was supported by the Olav Thon Foundation, the Research Council of Norway, and the Foundation for Research in Rheumatology. Some authors received speaker fees, participated in advisory boards, served as consultants, or had other ties with some pharmaceutical companies and institutions.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.