Coma Canella I, López-Sendon J
Arch Inst Cardiol Mex. 1980 Jul-Aug;50(4):497-503.
We have compared the systolic time intervals, cardiac index and stroke index in 15 patients with complete atrio-ventricular block and ventricular rate of less than 50 beats per minute. In all of them we placed a Swan-Ganz thermodilution catheter into the pulmonary trunk and transvenous temporary pacing in right ventricular cavity. In each patient we have simultaneously measured the systolic time intervals and cardiac output with different pacing rates, ranging between 50 and 120 beats per minute. With increasing heart rates we observed the following: PEP did not suffer significative changes; LVET and QS2 always decreased, and the ratio PEP/LVET increased in a constant manner. We could not find any statistical correlation between cardiac index and PEP/LVET; but the individual correlation between stroke index and PEP/LVET was very significant in each patient (r > -0.900). This proves that PLEP/LVET suffer modifications when changes in heat rate occur due to the LVET which reflects the changes of stroke index. This fact must be kept in mind when drugs which change heart rate without inotropic action are used.
我们比较了15例完全性房室传导阻滞且心室率低于每分钟50次的患者的收缩期时间间期、心脏指数和每搏指数。我们给所有患者在肺动脉干置入一根Swan - Ganz热稀释导管，并在右心室腔进行经静脉临时起搏。在每位患者中，我们同时测量了不同起搏频率（每分钟50至120次）下的收缩期时间间期和心输出量。随着心率增加，我们观察到以下情况：射血前期（PEP）没有显著变化；左室射血时间（LVET）和QS2总是降低，并且PEP/LVET比值以恒定方式增加。我们未发现心脏指数与PEP/LVET之间存在任何统计学相关性；但每搏指数与PEP/LVET之间的个体相关性在每位患者中都非常显著（r > -0.900）。这证明当心率因反映每搏指数变化的LVET而发生改变时，PEP/LVET会发生变化。在使用不具有变力作用而改变心率的药物时，必须牢记这一事实。
