OBSTRUCTION IN HYPERTROPHIC CARDIOMYOPATHY--ANALYSIS BY DOPPLER ECHOCARDIOGRAPHY

在心脏病学中，关于是否真的流出，一直存在着重大争议 肥厚型心肌病患者可能存在梗阻 腹主动脉下压差。在本研究中，距离选通多普勒超声心动图 对50例肥厚性心脏病患者进行了研究。 心肌病组和20例正常对照组。 在梗阻性肥厚型心肌病中，左室射血 特点是早期和快速排空(75%/14%的主动脉 收缩初期的1/3处的流速)。所占比例 二尖瓣-间隔接触后发生前向血流(因此 与梯度和脑室内压升高有关) 相当可观，平均超过40%。 收缩中期阻抗与左心室流出道的关系 二尖瓣间隔合并主动脉血流速度正常者的快速减速 接触性主动脉瓣部分关闭和过早关闭。此外，左翼 心室射血时间延长(384+/-40毫秒)， 心室持续排空和缩短，在这段时间里， 压力梯度和显著升高的脑室内压力 现在时。 相比之下，非梗阻性肥厚性心肌病患者表现出 没有证据表明左心室射血有阻抗。主动脉 流速波形与正常相似，但流速持续到 主动脉瓣关闭；显著的收缩期前向运动和部分 主动脉瓣收缩中期关闭不全，收缩期射血 周期正常(303正/负27毫秒)。 因此，在肥厚型心肌病患者中，二尖瓣收缩 前向运动构成左心室机械性梗阻 正在清空。这种二尖瓣运动产生的梯度似乎是 左心室持续收缩的病理生理学重要性 在脑室内压显著升高的情况下。

A major controversy persists in cardiology as to whether true outflow obstruction may exist in patients with hypertrophic cardiomyopathy and subaortic gradients. In this study range-gated Doppler echocardiography was utilized to investigate this problem in 50 patients with hypertrophic cardiomyopathy and 20 normals. In obstructive hypertrophic cardiomyopathy, left ventricular ejection was characterized by early and rapid emptying (75\plus/minus\14% of aortic flow-velocity in the initial one-third of systole). The proportion of forward flow occurring after mitral-septal contact (and therefore concommitant with the gradient and elevated intraventricular pressure) was considerable, averaging over 40%. Mid-systolic impedance to left ventricular outflow was suggested by the rapid deceleration in aortic flow-velocity concommitant with mitral-septal contact and premature partial aortic valve closure. Furthermore, left ventricular ejection was prolonged (384\plus/minus\40 msec) and the ventricle continued to empty and shorten during the period when both the pressure gradient and markedly elevated intraventricular pressures were present. In contrast, patients with nonobstructive hypertrophic cardiomyopthy showed no evidence of impedance to left ventricular ejection. Aortic flow-velocity waveforms were similar to normals, with flow persisting to aortic valve closure; significant systolic anterior motion and partial mid-systolic aortic valve closure were absnet, and the systolic ejection period was normal (303\plus/minus\27 msec). Hence, in patients with hypertrophic cardiomyopathy mitral valve systolic anterior motion constitutes the mechanical obstruction to left ventricular emptying. Gradients produced by this mitral valve motion appear to be of patho-physiologic importance since the left ventricle continues to contract in the presence of markedly elevated intraventricular pressures.