The prevalence of early repolarization in patients with noncompaction cardiomyopathy presenting with malignant ventricular arrhythmias

Early Repolarization in Noncompaction Cardiomyopathy. Background: Early repolarization (ER) is associated with malignant ventricular arrhythmias, including ventricular fibrillation (VF) and sudden cardiac death (SCD). One possible mechanism is increased trabeculation with deep intramyocardial invagination, carrying the Purkinje system deeper into the myocardium resulting in delayed depolarization and inhomogenous repolarization. Noncompaction cardiomyopathy (NCCM) is a recently classified, primary cardiomyopathy with excessive trabeculations. In these patients ventricular arrhythmias, including sustained VT and VF, occur frequently. The aim of this study was to determine the prevalence of ER in NCCM patients, especially in those primarily presenting with malignant ventricular arrhythmias or SCD. Methods: We analyzed prospective data from our NCCM registry including 84 patients, median age: 40 (3–79) years. Results: Fourteen patients (17%) initially presented with sustained VT (n = 5) or VF (n = 9) and 70 (83%) with heart failure or else. After the exclusion of 20 patients with the left bundle branch block, 25 (39%) NCCM patients had ER; 3 (6%) located in inferior leads, 14 (27%) in lateral leads, and 8 (15%) in both. None had ER in leads V1 to V3. In those presenting with VT/VF, 9/12 (75%) had ER (2 in inferior leads, 3 in lateral leads and 4 in both), versus 16/52 (31%) in the other patients (P = 0.02). If the NCCM population was dichotomized according to the presence or absence of ER, the long‐term outcome for VT/VF appeared worse in the ER positive patients (P = 0.05). Conclusion: There is a high prevalence of ER in NCCM patients, especially in those who present with malignant ventricular arrhythmias. (J Cardiovasc Electrophysiol, Vol. 23, pp. 938‐944, September 2012)