Antiarrhythmic Drug Cibenzoline Attenuates Left Ventricular Pressure Gradient and Improves Transmitral Doppler Flow Pattern in Patients With Hypertrophic Obstructive Cardiomyopathy Caused by Midventricular Obstruction

Background Recent interventional and surgical therapies to attenuate left ventricular pressure gradient (LVPG) can be difficult to perform in patients with hypertrophic obstructive cardiomyopathy (HOCM) cuased by midventricular obstruction (MVO), owing to the risk of inducing or deteriorating mitral regurgitation. Methods and Results The effects of the antiarrhythmic drug, cibenzoline, on LVPG and left ventricular (LV) diastolic function estimated by the change in the transmitral Doppler flow pattern were examined in 23 patients with HOCM and MVO. Hemodynamic changes 2 h after a single dose of 200 mg of cibenzoline and 3 months after oral administration of 300-450 mg of cibenzoline per day were examined. At 2 h after the treatment, LVPG decreased from 79±37 mmHg to 24±21 mmHg (p