Towne W D, Patel R, Cruz J B, Rathod R, Mirrer B
Chest. 1980 Feb;77(2):223-6. doi: 10.1378/chest.77.2.223.
A patient of faintly marfanoid habitus with left venticular failure, aortic regurgitation, and rate-related left bundle-branch block was found to have a midsystolic click and echocardiographic findings suggestive of mitral valve prolapse; however, the click did not move earlier in systole in response to head-up tilt or atrial pacing. Cardiac catheterization and angiocardiographic studies revealed severe left ventricular dysfunction out of proportion to the moderate amount of aortic regurgitation observed on aortographic study. Mitral valve prolapse was not confirmed by left ventriculographic study. Intracardiac phonocardiographic and catheter-tip manometric studies identified the click as being aortic in origin, ejection in timing, and midsystolic, rather than early systolic, because of delayed aortic valve opening related to left ventricular dysfunction and delay in conduction.
一名有轻度马方综合征体型的患者，伴有左心室衰竭、主动脉瓣反流和心率相关的左束支传导阻滞，发现有收缩中期喀喇音，超声心动图检查结果提示二尖瓣脱垂；然而，该喀喇音在收缩期并未因抬头倾斜或心房起搏而提前出现。心导管检查和心血管造影研究显示，严重的左心室功能障碍与主动脉造影研究中观察到的中度主动脉瓣反流程度不相称。左心室造影研究未证实二尖瓣脱垂。心内心音图和导管尖端测压研究确定该喀喇音起源于主动脉，时间为射血期，且为收缩中期而非收缩早期，这是由于与左心室功能障碍相关的主动脉瓣开放延迟和传导延迟所致。
