In reply: Long QT syndrome

In Reply: In contrasting the findings of two recent papers on long QT syndrome in children and in adults age 40 years or older, Dr. Ramaraj makes an excellent point—ie, that risk stratification strategies need to be age-dependent.^1,2 We agree with him and thank him for calling the readers’ attention to the issue. Apropos of his letter, we wish to highlight additional data recently published from the long QT syndrome registry summarizing the age-dependent relationships for risk of aborted cardiac arrest or death in long QT syndrome between ages 1 and 75.^3–5 Notably, beta-blocker therapy reduced risk at all ages, although the effect was of borderline significance in the older age groups.

Specifically, we would also like to stress the work of Sauer et al⁴ that deals specifically with patients ages 18 to 40. Their study demonstrated the ability to use sex, genotype, QTc, and history of cardiac events as risk stratification tools in long QT syndrome patients. Specifically, Sauer et al found that:

• Patients with LQT2 are at greater risk of arrhythmic events than patients with LQT1 or LQT3.
• QTc remained a significant predictor of events in this cohort.
• Aborted cardiac arrest or sudden death was related to QTc ≥ 500 ms, female sex, and having experienced a syncopal event after the age of 18.
• 
  Beta-blocker therapy resulted in a 60% reduction in risk; most of that risk reduction was in the LQT1 and LQT2 genotypes.

Table 1 highlights the major risk factors for life-threatening events (as opposed to syncope alone) in patients across the spectrum of age.

In Reply: In contrasting the findings of two recent papers on long QT syndrome in children and in adults age 40 years or older, Dr. Ramaraj makes an excellent point—ie, that risk stratification strategies need to be age-dependent.^1,2 We agree with him and thank him for calling the readers’ attention to the issue. Apropos of his letter, we wish to highlight additional data recently published from the long QT syndrome registry summarizing the age-dependent relationships for risk of aborted cardiac arrest or death in long QT syndrome between ages 1 and 75.^3–5 Notably, beta-blocker therapy reduced risk at all ages, although the effect was of borderline significance in the older age groups.

Specifically, we would also like to stress the work of Sauer et al⁴ that deals specifically with patients ages 18 to 40. Their study demonstrated the ability to use sex, genotype, QTc, and history of cardiac events as risk stratification tools in long QT syndrome patients. Specifically, Sauer et al found that:

• Patients with LQT2 are at greater risk of arrhythmic events than patients with LQT1 or LQT3.
• QTc remained a significant predictor of events in this cohort.
• Aborted cardiac arrest or sudden death was related to QTc ≥ 500 ms, female sex, and having experienced a syncopal event after the age of 18.
• 
  Beta-blocker therapy resulted in a 60% reduction in risk; most of that risk reduction was in the LQT1 and LQT2 genotypes.

Table 1 highlights the major risk factors for life-threatening events (as opposed to syncope alone) in patients across the spectrum of age.

In Reply: In contrasting the findings of two recent papers on long QT syndrome in children and in adults age 40 years or older, Dr. Ramaraj makes an excellent point—ie, that risk stratification strategies need to be age-dependent.^1,2 We agree with him and thank him for calling the readers’ attention to the issue. Apropos of his letter, we wish to highlight additional data recently published from the long QT syndrome registry summarizing the age-dependent relationships for risk of aborted cardiac arrest or death in long QT syndrome between ages 1 and 75.^3–5 Notably, beta-blocker therapy reduced risk at all ages, although the effect was of borderline significance in the older age groups.

Specifically, we would also like to stress the work of Sauer et al⁴ that deals specifically with patients ages 18 to 40. Their study demonstrated the ability to use sex, genotype, QTc, and history of cardiac events as risk stratification tools in long QT syndrome patients. Specifically, Sauer et al found that:

• Patients with LQT2 are at greater risk of arrhythmic events than patients with LQT1 or LQT3.
• QTc remained a significant predictor of events in this cohort.
• Aborted cardiac arrest or sudden death was related to QTc ≥ 500 ms, female sex, and having experienced a syncopal event after the age of 18.
• 
  Beta-blocker therapy resulted in a 60% reduction in risk; most of that risk reduction was in the LQT1 and LQT2 genotypes.

Table 1 highlights the major risk factors for life-threatening events (as opposed to syncope alone) in patients across the spectrum of age.