Maron B J, Gottdiener J S, Arce J, Rosing D R, Wesley Y E, Epstein S E
J Am Coll Cardiol. 1985 Jul;6(1):1-18. doi: 10.1016/s0735-1097(85)80244-8.
To determine whether true obstruction to left ventricular ejection exists in patients with hypertrophic cardiomyopathy and a subaortic gradient, pulsed Doppler echocardiography was used to analyze the patterns of left ventricular emptying in 50 patients with hypertrophic cardiomyopathy (20 with and 30 without evidence of obstruction) and in 20 normal subjects. In obstructive hypertrophic cardiomyopathy, left ventricular ejection was characterized by early and rapid emptying (76 +/- 14% of aortic flow velocity in the initial one-third of systole). The proportion of forward flow velocity occurring before initial mitral-septal contact (and hence, by inference before the onset of the subaortic gradient) was variable, but averaged 58%. In contrast, the proportion of forward flow velocity occurring after mitral-septal contact (and, therefore, concomitant with the gradient and increased intraventricular pressure) was considerable, averaging over 40%. Mid-systolic impedance to left ventricular outflow was suggested by the rapid deceleration in aortic flow velocity concomitant with mitral-septal contact and premature partial aortic valve closure. Furthermore, left ventricular ejection was prolonged (384 +/- 40 ms) and the ventricle continued to empty and shorten during the period when both the pressure gradient and markedly increased intraventricular pressures were present. In 16 of 20 patients, a relatively small second peak in flow velocity appeared in late systole. Since marked systolic anterior motion of the mitral valve was still present, the late systolic portion of forward flow velocity also appeared to be largely ejected during imposition of a mechanical impediment to outflow. In contrast, patients with nonobstructive hypertrophic cardiomyopathy showed no evidence of impedance to left ventricular ejection. Aortic flow velocity waveforms were similar to those of normal subjects, with flow persisting to aortic valve closure; significant mitral systolic anterior motion and partial mid-systolic aortic valve closure were absent, and the systolic ejection period was normal (303 +/- 27 ms).(ABSTRACT TRUNCATED AT 400 WORDS)
为了确定肥厚型心肌病伴主动脉瓣下压差的患者是否存在真正的左心室射血梗阻，采用脉冲多普勒超声心动图分析了50例肥厚型心肌病患者（20例有梗阻证据，30例无梗阻证据）及20例正常受试者的左心室排空模式。在梗阻性肥厚型心肌病中，左心室射血的特点是早期快速排空（在收缩期最初三分之一时间内主动脉血流速度的76±14%）。二尖瓣前叶与室间隔最初接触前（因此，据推断在主动脉瓣下压差出现之前）出现的前向血流速度比例各不相同，但平均为58%。相比之下，二尖瓣前叶与室间隔接触后（因此，与压差和心室内压升高同时出现）出现的前向血流速度比例相当可观，平均超过40%。二尖瓣前叶与室间隔接触及主动脉瓣过早部分关闭时主动脉血流速度迅速减慢，提示存在收缩中期左心室流出道阻抗。此外，左心室射血时间延长（384±40毫秒），在压力梯度和心室内压明显升高期间，心室继续排空并缩短。20例患者中有16例在收缩晚期出现相对较小的流速第二峰值。由于二尖瓣仍有明显的收缩期前向运动，收缩晚期前向血流速度部分似乎也是在存在机械性流出道梗阻时射出的。相比之下，非梗阻性肥厚型心肌病患者未显示左心室射血存在阻抗的证据。主动脉血流速度波形与正常受试者相似，血流持续至主动脉瓣关闭；无明显的二尖瓣收缩期前向运动和收缩中期主动脉瓣部分关闭，收缩期射血期正常（303±27毫秒）。（摘要截短至400字）
