Bloch K E, Jugoon S, Sackner M A
Division of Pulmonary Diseases, University of Miami, Mount Sinai Medical Center, Miami Beach, Fla.
Chest. 1994 Dec;106(6):1668-74. doi: 10.1378/chest.106.6.1668.
Thoracocardiography noninvasively estimates left ventricular performance by recording ventricular volume curves with inductive plethysmography. We studied timing of these curves to evaluate their potential to accurately track systolic time intervals in comparison with standard methods. Thoracocardiographic left ventricular volume curves, carotid pressure pulses determined by applanation tonometry, the phonocardiogram and ECG were recorded simultaneously in ten normal subjects at various body positions achieved with a tilt table. An equation was derived to predict preejection period from onset of ejection in thoracocardiographic curves. Ventricular ejection time was calculated as total electromechanical systole obtained by phonocardiography minus preejection period. The equation was validated prospectively in 31 measurements in critically ill patients. In normal subjects, the interval ECG Q wave to ejection onset in thoracocardiographic curves correlated well with preejection period from applanation tonometry and phonocardiography (r = 0.92; standard error of estimate (SEE), 8 ms; p < 0.001). Thoracocardiographic curves showed a delay that varied with body position according to the regression equation: delay = 40 ms + 10 x sine (tilt angle) (where r = 0.62; SEE, 7 ms; p < 0.001). Application of this equation in the prospective study in patients revealed close agreement in systolic time intervals from thoracocardiography and simultaneous applanation tonometry plus phonocardiography, respectively. The mean difference +/- SD between methods in preejection periods was 3 +/- 7 ms and in the ratios of preejection period to left ventricular ejection time, 0.02 +/- 0.05. Trends of changes in systolic time intervals were identical for the two methods. We conclude that thoracocardiography combined with phonocardiography provides accurate systolic time intervals when corrected for a position-dependent delay of its waveforms.
胸廓心动描记术通过用感应体积描记法记录心室容积曲线来无创地估计左心室功能。我们研究了这些曲线的时间，以评估其与标准方法相比准确追踪收缩期时间间期的潜力。在10名正常受试者中，使用倾斜台使其处于不同体位，同时记录胸廓心动描记术的左心室容积曲线、应用压平式眼压计测定的颈动脉压力脉搏、心音图和心电图。推导了一个方程，用于根据胸廓心动描记术曲线中射血开始来预测射血前期。心室射血时间计算为通过心音图获得的总机电收缩期减去射血前期。该方程在31例危重病患者的测量中进行了前瞻性验证。在正常受试者中，胸廓心动描记术曲线中心电图Q波至射血开始的间期与应用压平式眼压计和心音图测得的射血前期相关性良好（r = 0.92；估计标准误差（SEE），8毫秒；p < 0.001）。胸廓心动描记术曲线显示出一种延迟，根据回归方程，该延迟随体位变化：延迟 = 40毫秒 + 10×正弦（倾斜角度）（其中r = 0.62；SEE，7毫秒；p < 0.001）。该方程在患者的前瞻性研究中的应用表明，胸廓心动描记术与同时进行的压平式眼压计和心音图测量的收缩期时间间期分别密切一致。两种方法在射血前期的平均差异±标准差为3±7毫秒，在射血前期与左心室射血时间的比值方面为0.02±0.05。两种方法收缩期时间间期的变化趋势相同。我们得出结论，胸廓心动描记术结合心音图在对其波形的体位依赖性延迟进行校正后可提供准确的收缩期时间间期。
