18:00 〜 19:00
[P24-01] Prognostic values of QT dynamics in children with genotyped long QT syndrome
キーワード：long QT、QT dynamics、sudden death
【Background】QT dynamics has been used for diagnostic tool of ventricular repolarization abnormality such as long QT syndrome (LQT). We hypothesize that high risk LQT patients having symptoms have more abnormal QT dynamics compared with asymptomatic patients.【Methods and Results】Study population consists of 24 genotyped LQT children (12 LQT3, 3 LQT2, 5 LQT1, and 3 other genotype). Symptoms includes aborted sudden cardiac death, syncope during/ after exercise. Risk factors for such symptoms was evaluated between symptomatic subjects (n=5; 3LQT1, 2LQT3) and asymptomatic subjects (n= 19). We evaluated the QT/ heart rate (HR) relationship during treadmill exercise testing and the following face immersion test. A linear regression analysis was performed to determine the QT/HR slope and intercept. The QT/HR slopes were steeper in symptomatic LQT compare to asymptomatic LQT during the exercise and FI tests: -3.4 ± 0.7 vs. -2.0 ± 0.3, (p=0.07). Logistic regression analysis revealed that QT/ HR slope at recovery is a predictor for the symptom (p＜0.05).【Conclusions】Our observations suggest that symptomatic LQT patients tend to have steeper QT/HR slope compared to asymptomatic patients, especially, non-LQT3 subjects. QT dynamics may be useful in identifying high-risk patients and may help select an optimal antiarrhythmic therapeutic strategy.