急性心筋梗塞発症時の僧帽弁閉鎖不全症—冠動脈血栓溶解療法からの検討

Mitral regurgitation in acute myocardial infarction:Evaluation of the cases with thrombolytic treatment

　これまで急性期心筋梗塞において，僧帽弁閉鎖不全（MR）についての検討は数多く存在する^3〜7）。しかし，これまでの報告は，乳頭筋断裂による死亡例の検討が主であり，それ以外は，MRの診断と収縮期雑音との関連性についての報告がみられたにすぎない。また，死亡例を対象としている場合が多く，その臨床的意義は不明である。今回われわれは，急性期心筋梗塞に，冠動脈血栓溶解療法（PTCR）を施行した症例において，24時間以内に2-D doppler echoを施行し，その発症メカニズム，臨床的意義について検討したので報告する。

We evaluated the incidence of mitral regurgitation (MR) by 2-dimensional doppler color echocardiogra-phy (Aloca SSD-880) in serial 24 patients with acute phase of myocardial infarction (AMI) treated by thrombolysis. MR was observed in 9 patients (38%), indicating higher incidence of MR than that in patients with angina pectoris (8.3%). MR was seen 3/12 of MI with anterior descending coronary arterial involve-ment, 4/8 with right coronary artery and 2/4 with left circumflex artery. There was no statistical difference in occurence of MR among the three groups. Neither existance of mitral valve prolapse nor left ventricular end diastolic volume showed relation to MR in AMI, but in the group of decreased inferior wall motion there were many MRs. MRs were complicated frequently by inferior myocardial infarction due to right coronary involvement with a PCK more than 1200 IU and by those due to left circumflex arterial involvement with left coronary dominancy. Successful thrombolysis in patients with inferior myocardial infarction decreased the incidence of MRs.