Clinical significance of syncope in the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial

Background Syncope may portend risk of death, but which patients with synco pe are at high risk remains unclear. Objective The ESVEM trial, a multicenter randomized prospective trial, prov ided the opportunity to compare mortality rates of patients enrolled with s yncope to those enrolled with spontaneous ventricular arrhythmias. Methods patients enrolled in the ESVEM trial presenting with syncope alone (25 patients) or in combination with ventricular tachycardia (24 patients) were compared with patients with spontaneous ventricular tachycardia alone (332 patients) or ventricular fibrillation (105 patients). All patients had ventricular tochyarrhythmias induced at electrophysiology testing of great er than or equal to 10 premature ventricular complexes per hour on Holter m onitor. Results Of all patients randomly assigned, arrhythmic death and total morta lity rates were the same for those with syncope alone, with ventricular tac hycardia and syncope, with ventricular tachycardia alone, or with ventricul ar fibrillation. At 1 year, arrhythmic and total mortality rate for all pat ients was 21% and 24%, respectively; for patients with syncope alone, 30% a nd 29%, respectively (P = NS). At 4 years, arrhythmic death and total morta lity rate for: all patients was 33% and 42%, respectively; for patients wit h syncope alone, 37% and 42%, respectively (P = NS). Conclusion Syncope, associated with induced ventricular tachyarrhythmias at electrophysiologic testing, indicates high risk for death, similar to that of patients with documented spontaneous ventricular tachyarrhythmias.