Brickner M E, Starling M R
Department of Internal Medicine, University of Michigan, Ann Arbor 48105.
Circulation. 1990 Apr;81(4):1277-86. doi: 10.1161/01.cir.81.4.1277.
To determine whether left ventricular (LV) end systole and end ejection uncouple in patients with long-term mitral regurgitation, 59 patients (22 control patients with atypical chest pain, 21 patients with aortic regurgitation, and 16 patients with mitral regurgitation) were studied with micromanometer LV catheters and radionuclide angiograms. End systole was defined as the time of occurrence (Tmax) of the maximum time-varying elastance (Emax), and end ejection was defined as the time of occurrence of minimum ventricular volume (minV) and zero systolic flow as approximated by the aortic dicrotic notch (Aodi). The temporal relation between end systole and end ejection in the control patients was Tmax (331 +/- 42 [SD] msec), minV (336 +/- 36 msec), and then, zero systolic flow (355 +/- 23 msec). This temporal relation was maintained in the patients with aortic regurgitation. In contrast, in the patients with mitral regurgitation, the temporal relation was Tmax (266 +/- 49 msec), zero systolic flow (310 +/- 37 msec, p less than 0.01 vs. Tmax), and then, minV (355 +/- 37 msec, p less than 0.001 vs. Tmax and p less than 0.01 vs. Aodi). Additionally, the average Tmax occurred earlier in the patients with mitral regurgitation than in the control patients and patients with aortic regurgitation (p less than 0.01, for both), whereas the average time to minimum ventricular volume was similar in all three patient groups. Moreover, the average time to zero systolic flow also occurred earlier in the patients with mitral regurgitation than in the control patients (p less than 0.01) and patients with aortic regurgitation (p less than 0.05). Because of the dissociation of end systole from minimum ventricular volume in the patients with mitral regurgitation, the end-ejection pressure-volume relations calculated at minimum ventricular volume did not correlate (r = -0.09), whereas those calculated at zero systolic flow did correlate (r = 0.88) with the Emax slope values. We conclude that end ejection, defined as minimum ventricular volume, dissociates from end systole in patients with mitral regurgitation because of the shortened time to LV end systole in association with preservation of the time to LV end ejection due to the low impedance to ejection presented by the left atrium. Therefore, pressure-volume relations calculated at minimum ventricular volume might not be useful for assessing LV chamber performance in some patients with mitral regurgitation.
为了确定长期二尖瓣反流患者的左心室（LV）收缩末期和射血末期是否解耦，对59例患者（22例非典型胸痛对照患者、21例主动脉瓣反流患者和16例二尖瓣反流患者）进行了微测压左心室导管和放射性核素血管造影研究。收缩末期定义为最大时变弹性（Emax）出现的时间（Tmax），射血末期定义为最小心室容积（minV）出现的时间以及由主动脉重搏切迹（Aodi）近似的零收缩期血流出现的时间。对照患者中收缩末期和射血末期的时间关系为Tmax（331±42[标准差]毫秒）、minV（336±36毫秒），然后是零收缩期血流（355±23毫秒）。这种时间关系在主动脉瓣反流患者中得以维持。相比之下，在二尖瓣反流患者中，时间关系为Tmax（266±49毫秒）、零收缩期血流（310±37毫秒，与Tmax相比p<0.01），然后是minV（355±37毫秒，与Tmax相比p<0.001，与Aodi相比p<0.01）。此外，二尖瓣反流患者的平均Tmax出现时间早于对照患者和主动脉瓣反流患者（两者p均<0.01），而所有三组患者达到最小心室容积的平均时间相似。而且，二尖瓣反流患者达到零收缩期血流的平均时间也早于对照患者（p<0.01）和主动脉瓣反流患者（p<0.05）。由于二尖瓣反流患者的收缩末期与最小心室容积解耦，在最小心室容积时计算的射血末期压力-容积关系不相关（r=-0.09），而在零收缩期血流时计算的关系与Emax斜率值相关（r=0.88）。我们得出结论，在二尖瓣反流患者中，定义为最小心室容积的射血末期与收缩末期解耦，这是因为左心室收缩末期时间缩短，同时由于左心房提供的低射血阻抗，左心室射血末期时间得以保留。因此，在某些二尖瓣反流患者中，在最小心室容积时计算的压力-容积关系可能无助于评估左心室腔功能。
