Xiao H B, Jin X Y, Gibson D G
Cardiac Department, Royal Brompton Hospital, London.
Br Heart J. 1995 Jan;73(1):53-60. doi: 10.1136/hrt.73.1.53.
To assess the left ventricular pressure pulse, in particular its time course, reconstructed from the continuous wave Doppler signal of functional mitral regurgitation using the simplified Bernoulli equation.
Prospective study with simultaneously recorded high fidelity left ventricular pressure and continuous wave Doppler traces of functional mitral regurgitation, along with indirect left atrial pressure, electrocardiograms, and phonocardiograms.
Tertiary referral cardiac centre.
9 patients (age 60 (17) years) were studied immediately before or 1-20 h after routine cardiac surgery.
104 cardiac cycles were analysed. There were no consistent differences between directly measured and reconstructed pressures in the time intervals from Q to + dP/dt (mean (SD) 125 (35) v 130 (35) ms and from Q to -dP/dt (389 (30) v 387 (28) ms or from Q to maximum pressure (267 (40) v 270 (40) ms, all P = NS). The time from Q to the onset of pressure rise (67 (30) v 64 (30) ms, P < 0.01) and the duration of total left ventricular systole (404 (50) v 408 (50) ms, P < 0.01) measured by the two methods were effectively identical, though the small difference was consistent enough to be statistically significant. The calculated peak pressure drop between the left ventricle and the left atrium (45-100 mm Hg) significantly underestimated left ventricular pressure (72-150 mm Hg; 70 (11) v 105 (15) mm Hg, P < 0.01) even if mean left atrial pressure (14 (4.0) mm Hg) was taken into account. Compared with those directly derived from left ventricular pressure, values of pressure measured at + dP/dt (26 (6.5) v 53 (10) mm Hg, P < 0.01) and -dP/dt (30 (8.0) v 60 (10) mm Hg, P < 0.01), and those of the rates of increase (675 (155) v 815 (155) mm Hg/s, P < 0.01) and fall (610 (145) v 845 (175) mm Hg, P < 0.01) were all significantly underestimated by Doppler. The underestimation in peak rates of pressure change could not entirely be explained by a scaling effect of absolute pressure. To investigate interrelations between the two methods throughout the cardiac cycle, reconstructed left ventricular pressure was plotted against the direct record. The plots confirmed that the reconstructed pressure was always less than directly measured pressure, the relative degree of underestimation falling as the pressure rose. This was not the effect of acceleration but probably reflects changing geometry of the regurgitant orifice.
The continuous wave Doppler trace of functional mitral regurgitation is suitable for studying the timing of overall mechanical events and normalised rates of change of pressure in the left ventricle. Estimates of atrioventricular pressure drop by this method and particularly its absolute rates of change seem to be less reliable.
利用简化伯努利方程，评估从功能性二尖瓣反流的连续波多普勒信号重建的左心室压力脉冲，尤其是其时间进程。
前瞻性研究，同时记录高保真左心室压力、功能性二尖瓣反流的连续波多普勒轨迹，以及间接左心房压力、心电图和心音图。
三级转诊心脏中心。
9例患者（年龄60（17）岁）在常规心脏手术前或术后1 - 20小时接受研究。
分析了104个心动周期。从Q到 + dP/dt的时间间隔（平均（标准差）125（35）毫秒对130（35）毫秒）、从Q到 - dP/dt的时间间隔（389（30）毫秒对387（28）毫秒）或从Q到最大压力的时间间隔（267（40）毫秒对270（40）毫秒），直接测量压力与重建压力之间均无一致差异（所有P = 无统计学意义）。两种方法测量的从Q到压力上升起始点的时间（67（30）毫秒对64（30）毫秒，P < 0.01）以及左心室总收缩期持续时间（404（50）毫秒对408（50）毫秒，P < 0.01）实际上是相同的，尽管微小差异具有足够的一致性，具有统计学意义。即使考虑平均左心房压力（14（4.0）毫米汞柱），计算得出的左心室与左心房之间的峰值压力差（45 - 100毫米汞柱）仍显著低估了左心室压力（72 - 150毫米汞柱；70（11）毫米汞柱对105（15）毫米汞柱，P < 0.01）。与直接从左心室压力得出的值相比，在 + dP/dt时测量的压力值（26（6.5）毫米汞柱对53（10）毫米汞柱，P < 0.01）、在 - dP/dt时测量的压力值（30（8.0）毫米汞柱对60（10）毫米汞柱，P < 0.01）以及压力上升速率（675（155）毫米汞柱/秒对815（155）毫米汞柱/秒，P < 0.01）和下降速率（610（145）毫米汞柱对845（175）毫米汞柱，P < 0.01）均被多普勒显著低估。压力变化峰值速率的低估不能完全用绝对压力的缩放效应来解释。为研究整个心动周期中两种方法之间的相互关系，将重建的左心室压力与直接记录值进行绘图。这些图证实重建压力始终低于直接测量压力，随着压力升高，低估的相对程度下降。这不是加速度的影响，可能反映了反流口几何形状的变化。
功能性二尖瓣反流的连续波多普勒轨迹适用于研究左心室整体机械事件的时间以及压力变化的标准化速率。通过这种方法估计的房室压力差，尤其是其绝对变化速率似乎不太可靠。
