Lee C H, Vancheri F, Josen M S, Gibson D G
Cardiac Department, Royal Brompton and National Heart Hospital, London.
Br Heart J. 1990 Sep;64(3):214-8. doi: 10.1136/hrt.64.3.214.
Mitral valve cusp separation on M mode echogram, the mitral valve opening artefact, and the onset of forward transmitral flow recorded by Doppler echocardiography have all been taken to mark the end of isovolumic relaxation, while its onset has been taken either as the aortic closure sound (A2) recorded phonocardiographically or the aortic closure artefact determined by Doppler technique. Possible differences in the measurement of the isovolumic relaxation time were studied when these landmarks were used in 44 healthy people, 14 patients with mitral stenosis, 21 patients with left ventricular hypertrophy, and 24 patients with dilated cardiomyopathy by recording M mode echograms of the mitral valve, and pulsed and continuous wave Doppler spectra of transmitral flow, with simultaneous electrocardiograms and phonocardiograms. A2 was effectively synchronous with the aortic artefact. However, when the onset of Doppler flow was regarded as the end of isovolumic relaxation, the interval was significantly longer than when mitral cusp separation on M mode echograms was used: by 25 (10) ms in healthy individuals, by 25 (15) ms in patients with left ventricular hypertrophy, and by 50 (35) ms in patients with dilated cardiomyopathy. In patients with mitral stenosis the interval was only 5 (5) ms longer. The mitral valve opening artefact consistently followed the onset of flow and corresponded much more closely to the E point on the M mode echogram. This shows that it occurred during the rapid filling period and well beyond isovolumic relaxation by any definition. Thus isovolumic relaxation time measured from A2 to the onset of transmitral flow or the mitral valve opening artefact differs from that derived from A2 to mitral valve cusp separation. These intervals cannot be used interchangeably to measure "isovolumic relaxation time".
M型超声心动图上二尖瓣叶尖分离、二尖瓣开放伪像以及多普勒超声心动图记录的二尖瓣前向血流起始，均被用来标志等容舒张期末期，而其起始则被认为是心音图记录的主动脉瓣关闭音（A2）或多普勒技术确定的主动脉瓣关闭伪像。在44名健康人、14名二尖瓣狭窄患者、21名左心室肥厚患者和24名扩张型心肌病患者中，通过记录二尖瓣的M型超声心动图、二尖瓣血流的脉冲和连续波多普勒频谱，同时记录心电图和心音图，研究了使用这些标志时等容舒张时间测量的可能差异。A2与主动脉伪像有效同步。然而，当将多普勒血流起始视为等容舒张期末期时，该间期明显长于使用M型超声心动图上二尖瓣叶尖分离时：健康个体中长25（10）毫秒，左心室肥厚患者中长25（15）毫秒，扩张型心肌病患者中长50（35）毫秒。二尖瓣狭窄患者中该间期仅长5（5）毫秒。二尖瓣开放伪像始终跟随血流起始，并且与M型超声心动图上的E点更为接近。这表明它发生在快速充盈期，并且无论按照何种定义都远远超出等容舒张期。因此，从A2到二尖瓣前向血流起始或二尖瓣开放伪像测量的等容舒张时间与从A2到二尖瓣叶尖分离得出的等容舒张时间不同。这些间期不能相互替代用于测量“等容舒张时间”。
