Long Runs of Non‐Sustained Ventricular Tachycardia on 24‐Hour Ambulatory Electrocardiogram Predict Major Arrhythmic Events in Patients with Idiopathic Dilated Cardiomyopathy

Abstract

This study examined the prognostic significance of the rate and length of non-sustained (NS) ventricular tachycardia (VT) on 24-hour ambulatory electrocardiograms (ECG) recorded in 343 patients with idiopathic dilated cardiomyopathy (IDC) in the prospective Marburg Cardiomyopathy study. NSVT was defined as >/=3 consecutive ventricular premature beats at >120 bpm. During 52 +/- 21 months of follow-up, major arrhythmic events defined as sustained VT, VF, or sudden cardiac death occurred in 46 of 343 patients (13%). Patients with 3-4 beat runs of NSVT had a similar arrhythmia-free survival as patients without NSVT on baseline 24-hour ambulatory ECG. The incidence of major arrhythmic events during follow-up increased significantly from 2% per year in patients without NSVT, to 5% per year in patients with 5-9 beat runs of NSVT, to 10% per year in patients with >/=10 beat runs of NSVT (P < 0.05). Unlike the length, the rate of NSVT was similar in patients with versus without subsequent major arrhythmic events (163 +/- 23 vs 160 +/- 24 bpm). Thus, the length but not the rate of NSVT on 24-hour ambulatory ECG was a predictor of major arrhythmic events in patients with IDC. The presence of NSVT with >/=10 beat runs on ambulatory ECG was associated with a particularly high risk of major arrhythmic events.