New Technique for Determining Instantaneous Myocardial Force‐Velocity Relations in the Intact Heart
New Technique for Determining Instantaneous Myocardial Force‐Velocity Relations in the Intact Heart
复制标题
确定完整心脏瞬时心肌力-速度关系的新技术
作者：
W. Grossman;H. Brooks;S. Meister;H. Sherman;L. Dexter
一种新的技术，描述了心肌力-速度关系的瞬时测定。该方法采用心室内压对数的电子微分，产生（dP/dt）P−1（心室压上升速率[dP/dt]与同时心室压[P]的比值）的连续在线记录。另一种技术描述了力-速度矢量环的自动投影，以逐搏方式在纵坐标上显示（dP/dt）P−1，在横坐标上显示心室压力。通过常规方法测定的（dP/dt）P−1与通过使用对数放大器电路以电子方式导出的（dP/dt）P−1之间具有良好的相关性（r=0.982）。描述了实验研究，其记录了通过本方法确定的（dP/dt）P−1对已知影响心肌收缩性的干预的响应性。在输注CaCl 2、去甲肾上腺素和胰高血糖素后观察到（dP/dt）P−1增加，而在戊巴比妥后观察到下降。Inclusions（dP/dt）P−1是心肌收缩力的有效指标，本方法允许在各种情况下对心室功能的变化进行在线逐搏评估。
A new technique is described for the instantaneous determination of myocardial force-velocity relationships. The method employs electronic differentiation of the logarithm of intraventricular pressure, which yields a continuous on-line record of (dP/dt)P−1 (the ratio of the rate of rise of ventricular pressure [dP/dt] to the simultaneous ventricular pressure [P]). A further technique is described for the automatic projection of force-velocity vector loops, displaying (dP/dt)P−1 on the ordinate against ventricular pressure on the abscissa in a beat-to-beat fashion. An excellent correlation (r=0.982) was demonstrated between (dP/dt)P−1 determined by conventional methods and that derived electronically by use of the logarithmic amplifier circuit. Experimental studies are described which document the responsiveness of (dP/dt)P−1 determined by the present method to interventions known to affect myocardial contractility. An increase in (dP/dt)P−1 was observed following infusions of CaCl2, norepinephrine, and glucagon, and a decrease following pentobarbital. Insofar as (dP/dt)P−1 is a valid index of myocardial contractility, the present method permits on-line, beat-to-beat evaluation of changes in ventricular function under a variety of circumstances.