Triventricular pacing improved dyssynchrony in heart failure patient with right-bundle branch block and left anterior fascicular block.

The present case report describes a 53-year-old man with drug-resistant heart failure. Electrocardiogram showed complete right-bundle branch block and left anterior fascicular block. A cardiac resynchronization therapy (CRT) device was implanted in him because echocardiography showed obvious left ventricular dyssynchrony between septal and lateral walls. After CRT implantation, dyssynchrony was improved and ejection fraction was increased. Evaluation of coexisting left hemiblock and left ventricular dyssynchrony may be needed in patients with atypical indications for CRT. <Learning objective: Cardiac resynchronization therapy (CRT) for patients with complete right-bundle branch block (CRBBB) is still controversial. Presence of hemiblock and left ventricular dyssynchrony between the pacing sites may be essential to determine CRT indication even in patients with CRBBB.>.