Auditory stimuli as a trigger for arrhythmic events differentiate HERG-related (LQTS(2)) patients from KVLQT1-related patients (LQTS(1))

OBJECTIVE This study was performed to identify a possible relationship betw een genotype and phenotype in the congenital familial long QT syndrome (cLQ TS). BACKGROUND The cLQTS, which occurs as an autosomal dominant or recessive tr ait, is characterized by QT-interval prolongation on the electrocardiogram and torsade de pointes arrhythmias, which may give rise to recurrent syncop e or sudden cardiac death. Precipitators for cardiac events are exercise or emotion and occasionally acoustic stimuli. METHODS The trigger for cardiac events (syncope, documented cardiac arrhyth mias, sudden cardiac death) was analyzed in 11 families with a familial LQT S and a determined genotype. RESULTS The families were subdivided in KVLQT1-related families (LQTS(1), n = 5) and HERG (human ether-a-gogo-related gene)-related families (LQTS(2), n = 6) based on single-strand conformation polymorphism analysis and seque ncing. Whereas exercise-related cardiac events dominate the clinical pictur e of LQTS, patients, auditory stimuli as a trigger for arrhythmic events we re only seen in LQTS, patients. CONCLUSIONS Arrhythmic events triggered by auditory stimuli may differentia te LQTS(2) from LQTS(1) patients. (C) 1999 by the American College of Cardi ology.