田中 英治, 福田 信夫, 篠原 尚典, 武市 直樹, 添木 武, 板東 完治, 由井 靖子, 田村 禎通

Hideji TANAKA, Nobuo FUKUDA, Hisanori SHINOHARA, Naoki TAKEICHI, Takeshi SOEKI, Kanji BANDO, Yasuko YUI, Yoshiyuki TAMURA

国立善通寺病院循環器科・臨床研究部

Division of Cardiology and Clinical Research, Zentsuji National Hospital, 2-1-1 Zentsuji-shi, Senyu-cho, Kagawa-ken 765-0001, Japan

キーワード : Disopyramide, Doppler guide wire, Echocardiography, Hypertrophic obstructive cardiomyopathy, Left ventricular outflow tract

A 45-year-old woman with hypertrophic obstructive cardiomyopathy (HOCM) complained of syncope. Transthoracic echocardiography showed asymmetric septal hypertrophy and systolic anterior motion of the mitral valve. Doppler-derived pressure gradient was approximately 125 mmHg at the left ventricular outflow tract (LVOT). Coronary arteriograms showed no significant stenosis. Pressure gradient at the LVOT obtained by catheterization was approximately 100 mmHg and did not change with right ventricular pacing in the DDD mode. It decreased to 30 mmHg after intravenous administration of 25 mg of disopyramide over a period of 3 minutes and there was a concomitant decrease from 26 to 11 mmHg in LV end-diastolic pressure. In the coronary flow velocity curve, obtained by placing a Doppler guide wire in the left anterior descending artery, intravenous disopyramide caused a marked decrease in both systolic retrograde and diastolic antegrade flow velocities, an increase in acceleration slope, and a decrease in deceleration slope of the diastolic antegrade flow velocity curve. Of these changes, the decrease in systolic flow velocity and the decrease in deceleration slope of the diastolic flow velocity curve may be related to reduction in pressure gradient at the LVOT and subsequent decrease in LV diastolic pressure, respectively. The increase in acceleration slope of the diastolic flow velocity curve may be related to improvement in LV relaxation resulting from an effect resembling that of a calcium antagonist, and the decrease in diastolic flow velocity may be related to a peripheral vasoconstrictive effect of the coronary artery.