Patients with
catecholaminergic polymorphic ventricular tachycardia present at a young age with exercise-induced ventricular arrhythmias (VAs) and may have a positive family history. We describe 8 patients who presented with exercise-induced symptoms as adults, have a negative family history, and responded to beta-blocker
therapy. The study evaluated exercise treadmill electrocardiographic data from patients referred for exercise-induced VA. Inclusion criteria consisted of development of bidirectional, pleomorphic, or polymorphic
ventricular tachycardia with exercise, adult age at first onset, negative family history, and no evidence of structural
heart disease. We correlated VA configurations with respect to heart rate before and after beta-blocker
therapy. Patients displayed a pattern of increasing ventricular complexity with increasing heart rate. The appropriate beta blocker (n = 7) or
calcium channel blocker (n = 1) was defined as the dose that resulted in control of symptoms. Three patients showed suppression of VA with
sinus tachycardia at peak heart rate. Six patients had decreased VA defined as absence of higher complexity arrhythmias. With
drug therapy, average heart rate associated with
premature ventricular complex couplets/triplets increased, whereas duration and complexity of premature ventricular complexes decreased. One patient had an automatic implantable cardiac
defibrillator placed but has had no discharges from the device since starting the appropriate beta blocker. In conclusion, these patients appear to respond well to beta-blocker or
calcium channel blocker therapy with decreased ectopic complexity and an increased heart rate threshold for inducing VA.