The long QT interval syndrome. A Rosetta stone for sympathetic related ventricular tachyarrhythmias.

T he long QT interval syndrome (LQTS) has a low incidence in the general population, but, like the Wolff-Parkinson-White (WPW) syndrome , it has a major impact. While the WPW syndrome is the Rosetta stone of reentry, the LQTS may be the Rosetta Stone for ventricular tachyar-rhythmias dependent on sympathetic stimulation. Present Study In a recent issue of Circulation, Schwartz et all provided further evidence of this sympathetic link by demonstrating the beneficial effects of left-sided cardiac sympathetic denervation in 85 patients, 84 of whom (91%) continued to have syncope or cardiac arrest before denervation despite receiving ,3-adreno-ceptor blockade. After surgery, the number of patients with cardiac events, the number of cardiac events per patient, and the number of patients with five or more cardiac events all decreased significantly. However, there still were seven (8%) sudden deaths, reducing the 5-year survival to 94%. Importance Despite criticisms of study design-no controls, lack of uniform surgical procedure, continued oral therapy with ,B-adrenoceptor blockers in 84% of patients after surgery, and no reliable proof that all patients worldwide who underwent this procedure were included in the data analysis (e.g., did many physicians not report their surgical failures to the international registry?)-the study is important from several standpoints. First and foremost, it provides the most complete and important data found anywhere on a therapeutic modality for patients with symptomatic LQTS. Second, it offers a clue to the arrhythmogenic role of sympathetic stimulation (see below). Last, it is a fine example of international cooperation in medicine. The opinions expressed in this article are not necessarily those of the editors or of the American Heart Association. The idiopathic LQTS comprises three groups of patients with a congenital disorder characterized by abnormally prolonged ventricular repolarization that contributes to the development of ventricular tachy-arrhythmias, often torsades de pointes. The Jervell-Lange-Nielsen syndrome is transmitted as an autoso-mal recessive pattern and includes congenital neural deafness. Patients with the Romano-Ward syndrome have normal hearing and autosomal dominant transmission , whereas the sporadic form comprises a nonfamilial group with normal hearing.2,3 Hypotheses Any hypothesis put forth to explain this syndrome must account for all of its features, namely the long QT interval and abnormal T or TU waves, T wave alternans, a lower than normal heart rate especially in children, sinus pauses, and ventricular tachycar-dia, particularly torsades de pointes, that is usually precipitated by physical or emotional stress and causes syncope and …