Mitral regurgitation disappearance after cibenzoline treatment in a patient with hypertrophic obstructive cardiomyopathy

Hypertrophic obstructive cardiomyopathy (HOCM), which shows left ventricular outflow pressure gradient (LVPG), is often complicated with mitral regurgitation (MR). We examined a 62-year-old Japanese female with HOCM and MR. Ultrasound echocardiography showed severe MR, asymmetrical septal hypertrophy, systolic anterior movement of the mitral valve anterior leaflet, and left ventricular outflow stenosis. Her LVPG, measured using continuous wave Doppler recording, was 118 mmHg. During heart catheterization, the aortic pressure and left ventricular pressure were simultaneously measured. An intravenous injection of 70 mg cibenzoline decreased the LVPG from 110 mmHg to 16 mmHg. Left ventriculography was performed immediately after the injection and did not show MR. This clearly demonstrates that cibenzoline decreases LVPG in patients with HOCM and also improves the MR that arises from LVPG.