The haemodynamic importance of atrioventricular synchrony and rate increase at rest and during exercise.
The haemodynamic importance of atrioventricular synchrony and rate increase at rest and during exercise.
复制标题
房室同步性的血流动力学重要性以及静息和运动时心率增加。
作者：
B. Kristensson;K. Arnman;L. Rydén
为了比较房室同步对心率增加的血流动力学重要性，我们研究了10例房室传导阻滞除外的健康患者，这些患者接受了房室同步起搏器治疗。通过肱动脉和肺动脉插管获得血液动力学数据。记录在休息和直立自行车测力计在两个次最大的工作负荷（50%和80%的最大有氧运动耐力）。首先在房室同步起搏模式（VDD）下进行研究，随后在固定频率心室起搏（VVI）期间重复研究，心室率调整至房室同步起搏期间达到的水平。静止（平均心率74 bpm），保持房室同步性，增加心输出量（5.0 +/- 0.7 l min-1;平均值+/- SD）与正常对照组相比（4.5 +/- 1.0; P <0.05），由于每搏输出量较高（70 +/- 19 vs 64 +/- 22 ml; P <0.05），说明心房对心室充盈的重要性。在50%的运动中（平均心率122 bpm）和80%（平均心率146次/分）时，心输出量无显著差异（50%：VVI 10.1 ± 2.5，VDD 10.5 ± 1.6 NS; 80%：VVI 12.8 ± 4.1，VDD 12.3 ± 3.5，NS）或每搏输出量（50%：VVI 83 +/- 23，VDD 88 +/- 17，NS; 80%：VVI 89 +/- 32，VDD 85 +/- 27，NS）。我们的结论是，率增加的能力是非常重要的，而保存房室同步似乎是不太重要的个人的能力，以增加心输出量在运动中，至少在没有心肌疾病的患者。
To compare the added haemodynamic importance of atrioventricular synchrony to rate increase, we studied 10 patients, healthy except for atrioventricular block, treated with atrioventricular synchronous pacemakers. Haemodynamic data were obtained by brachial and pulmonary arterial catheterisation. Recordings were made at rest and during upright bicycle ergometry at two submaximal work loads (50% and 80% of maximal aerobic exercise tolerance). The investigation was first performed in the atrioventricular synchronous mode of pacing (VDD) and later repeated during fixed-rate ventricular pacing (VVI) at ventricular rates adjusted to the levels achieved during atrioventricular synchronous pacing. At rest (mean rate 74 bpm), preserved atrioventricular synchrony increased cardiac output (5.0 +/- 0.7 l min-1; mean +/- SD) compared with asynchrony (4.5 +/- 1.0; P less than 0.05), owing to a higher stroke volume (70 +/- 19 versus 64 +/- 22 ml; P less than 0.05), illustrating the importance of the atrial contribution to ventricular filling. During exercise at 50% (mean rate 122 bpm) and 80% (mean rate 146 bpm) of maximal aerobic tolerance, there were no significant differences in cardiac output (50%: VVI 10.1 +/- 2.5, VDD 10.5 +/- 1.6 NS; 80%: VVI 12.8 +/- 4.1, VDD 12.3 +/- 3.5, NS) or in stroke volume (50%: VVI 83 +/- 23, VDD 88 +/- 17, NS; 80%: VVI 89 +/- 32, VDD 85 +/- 27, NS). We conclude that the capacity for rate increase is of major importance while preserved atrioventricular synchrony seems to be much less important for the ability of the individual to increase cardiac output during exercise, at least in patients without myocardial disease.