The efficacy of cibenzoline for reducing the left ventricular pressure gradient of hypertrophic obstructive cardiomyopathy: A case report.

A 46 year-old man with hypertrophic obstructive cardiomyopathy (HOCM) was referred to this clinic complaining of shortness of breath. His symptoms remained even after he had been treated with bisoprolol, lisinopril, and verapamil. We started treating him with cibenzoline, instead of verapamil. Continuous-wave Doppler examination revealed a marked decrease from 95.9 mm Hg to 8.8 mmHg in the left ventricular outflow tract pressure gradient after administration of cibenzoline, and the symptom disappeared. The electrical axis of the electrocardiogram deviated from +53 to +95 degrees, and the QRS interval was increased from 0.095 to 0.114 seconds. By the M-mode echocardiogram, the interventricular septum was observed moved paradoxically in the early, systolic phase. We suggest the possibility that cibenzoline modifies intraventricular conduction and causes asynchronous contraction of the left ventricle, resulting in decrease in the left ventricular outflow tract pressure gradient.