Biventricular pacing worsened dyssynchrony in heart failure patient with right-bundle branch block.

The use of a biventricular pacing system for patients with complete right-bundle branch block (CRBBB) is still controversial. Although cardiac resynchronization therapy-defibrillator (CRT-D) was implanted in a heart failure patient with CRBBB, dyssynchrony worsened and stroke volume decreased, and this patient was re-admitted due to exacerbated heart failure. Therefore, evaluation of dyssynchrony and cardiac function after implantation of a biventricular pacing system may be needed in patients with atypical indications for CRT.