Smalcelj A, Gibson D G
Br Heart J. 1985 Apr;53(4):436-42. doi: 10.1136/hrt.53.4.436.
In order to investigate relations between mitral valve closure and mechanical events at the onset of left ventricular systole, simultaneous M mode echocardiograms and phonocardiograms were recorded with the apexcardiogram and its first differential (dA/dt) in 25 normal subjects and 88 patients with heart disease. The timing of mitral and aortic valve closure and the onset and peak rate of rise of the apexcardiogram with respect to the Q wave of the electrocardiogram were measured. There was considerable variation in the intervals from Q to mitral valve closure (Q-MVC) and from Q to peak dA/dt and in the isovolumic contraction time between normal subjects. There was no consistent abnormality of these intervals in patients with coronary artery or valvar disease, and no relation between the interval from Q to mitral valve closure and end diastolic pressure. When the timing of the first heart sound and peak dA/dt were considered together, however, clear abnormalities became apparent. In normal subjects, the intervals Q-MVC and Q to peak dA/dt were significantly correlated. In coronary artery disease, the expected relation between Q-MVC and Q to peak dA/dt was found only when end diastolic pressure was normal and was lost when end diastolic pressure was raised. Mitral stenosis was associated with delayed mitral closure in a few cases only, but in chronic aortic regurgitation closure was consistently early with respect to the apexcardiogram. In patients with atrial fibrillation and a normal mitral valve the timing of mitral valve closure with respect to the apexcardiogram was normal, which is inconsistent with an atrial contribution to the timing of mitral valve closure. Thus when considered in isolation the timing of mitral valve closure and the duration of isovolumic contraction time gave little information about cardiac function. Nevertheless, a predictable relation exists between mitral valve closure and the onset of left ventricular mechanical systole in normal subjects, which can be used to identify characteristic alterations in patients with heart disease.
为了研究二尖瓣关闭与左心室收缩期开始时机械事件之间的关系，对25名正常受试者和88名心脏病患者同时记录了M型超声心动图、心音图、心尖搏动图及其一阶导数（dA/dt）。测量了二尖瓣和主动脉瓣关闭的时间，以及心尖搏动图相对于心电图Q波的起始和上升峰值速率。正常受试者从Q波到二尖瓣关闭（Q-MVC）、从Q波到dA/dt峰值的间隔以及等容收缩时间存在相当大的差异。冠状动脉或瓣膜疾病患者这些间隔没有一致的异常，并且从Q波到二尖瓣关闭的间隔与舒张末期压力之间没有关系。然而，当同时考虑第一心音的时间和dA/dt峰值时，明显的异常就显现出来了。在正常受试者中，Q-MVC间隔和从Q波到dA/dt峰值的间隔显著相关。在冠状动脉疾病中，只有当舒张末期压力正常时，才会发现Q-MVC与从Q波到dA/dt峰值之间预期的关系，而当舒张末期压力升高时这种关系就消失了。二尖瓣狭窄仅在少数情况下与二尖瓣关闭延迟有关，但在慢性主动脉瓣反流中，相对于心尖搏动图，关闭始终较早。在心房颤动且二尖瓣正常的患者中，二尖瓣关闭相对于心尖搏动图的时间是正常的，这与心房对二尖瓣关闭时间的影响不一致。因此，单独考虑二尖瓣关闭时间和等容收缩时间的持续时间，对于心脏功能提供的信息很少。然而，在正常受试者中，二尖瓣关闭与左心室机械收缩期的开始之间存在可预测的关系，这可用于识别心脏病患者的特征性改变。
