ジソピラミドにより著明な圧較差の減少を認めた閉塞性肥大型心筋症の1例

A Case of Hypertrophic Obstructive Cardiomyopathy Significantly Improved by Disopyramide

　症例は35歳，女性．労作時呼吸困難と失神発作を主訴に入院．心エコー上心室中隔基部に限局した肥厚と左室流出路圧較差（圧較差）を認め閉塞性肥大型心筋症と診断した．圧較差に対してプロプラノロール単独投与が無効で，心カテーテル法によりDDDペーシングおよびジソピラミド投与が血行動態に及ぼす影響を検討した．右室心尖部のDDDペーシングにより圧較差は洞調律時124 mmHgより74 mmHgに減少した．一方，ジソピラミド静注では圧較差は110mmHgより2mmHgへと著明に減少し末梢血管抵抗の増大による体血圧の上昇，左室圧の減少が要因と考えられた．以後同薬剤の経口投与にて血中濃度を維持し再検査時に圧較差は50mmHgと減少効果が認められ，症状の再発を認めなかった．心室中隔基部に限局した肥厚を伴う閉塞性肥大型心筋症に対してジソピラミド投与が著効を示した1例を経験したので報告する．

A 35-year-old woman who had a history of shortness of breath on exertion and syncope was admitted to our hospital. Two-dimensional echocardiography revealed an isolated basal septal hypertrophy and a significant pressure gradient was obtained at the left ventricular outflow by continuous wave Doppler echocardiography. These findings indicated a diagnosis of hypertrophic obstructive cardiomyopathy. Although she had taken propranolol since admission, it was not effective in reducing the pressure gradient. Dual-chamber pacing and intravenous disopyramide administration were per. formed while the patient was undergoing cardiac cath-eterization-angiography. The pressure gradient de creased from 124 to 74 mmHg during pacing and from 110 to 2 mmHg 5 minutes after intravenous disopyr. amide administration. During the acute effect induced by disopyramide, the significant pressure gradient reduc tion seemed to be related to the increase of systolic aortic pressure induced by elevation of systemic periph. eral vascular resistance, and the decrease of systolic leftventricular pressure. The patient has continued to take oral disopyramide and follow-up catheterization has demonstrated favorable pressure gradient reduction. Our report thus concerns a case of a patient with hypertrophic obstructive cardiomyopathy. Acute intra-venous and continuous oral disopyramide administra-tion was effective in reducing the left ventricular outflow pressure gradient.