Left bundle branch block, atrioventricular block, torsade de pointes and long QT syndrome: is this too much for a rare cardiomyopathy?

Abstract

Left ventricular noncompaction (LVNC) is now recognized as a distinct form of cardiomyopathy with a clinical presentation and natural history of its own. Common manifestations of LVNC include heart failure, ventricular arrhythmias and embolic events, but serious atrioventricular conduction disturbances are rarely reported in the literature. The authors describe the case of a 40-year-old woman who went to the emergency department due to syncope. The ECG revealed left bundle branch block (LBBB) and 2:1 atrioventricular block (AVB) and the patient was admitted for pacemaker implantation. During hospitalization she developed torsade de pointes and complete AVB with increased QTc. The echocardiogram showed images compatible with LVNC. This case provides additional evidence that LVNC may be complicated by 2:1 (or complete) AVB, intraventricular conduction disturbances (LBBB) and repolarization abnormalities (long QT). This combination of electrocardiographic changes has rarely been reported in the literature. We describe a series of affected patients, focusing on electrocardiographic characteristics.