Facchini M, De Ferrari G M, Bonazzi O, Weiss T, Schwartz P J
Unità di Studio delle Aritmie, Università degli Studi di Milano, Italy.
Am J Cardiol. 1991 Aug 1;68(4):349-54. doi: 10.1016/0002-9149(91)90830-e.
To evaluate the antiarrhythmic effect of reflex-induced vagal activation, phenylephrine was infused in 17 patients with frequent ventricular premature complexes (VPCs). The role of heart rate reduction in suppressing VPCs was explored by pacing the atria at the preinfusion levels. Baroreceptor activation was considered effective when a greater than or equal to 20% decrease in heart rate was observed. Ten patients (59%) achieved the target heart rate decrease (-29 +/- 5%), whereas in 7 (41%) the baroreceptor reflex was considered inadequate. In the former group ("responders"), heart rate decreased from 73 +/- 7 to 52 +/- 6 beats/min (p less than 0.0001). When heart rate was allowed to fluctuate, ectopic activity was completely abolished in 9 of 10 patients; mean number of VPCs decreased from 38 +/- 8 to 0.2 +/- 0.6/100 beats (p less than 0.0001). During pacing, VPCs reappeared but their mean number (22 +/- 10/100 beats) was still significantly reduced compared with control values (p = 0.003). In the "nonresponders," despite adequate blood pressure increases, VPC frequency was not affected. The QT interval lengthened during phenylephrine (392 +/- 17 ms) versus control conditions (372 +/- 18 ms, p = 0.0008) in the responders group, whereas no change was observed in the nonresponders. These results demonstrate that reflex vagal activation markedly reduces VPCs. This effect is only partially rate-dependent; direct and indirect electrophysiologic changes secondary to baroreflex activation are also likely to be involved.
为评估反射性迷走神经激活的抗心律失常作用，对17例频发室性早搏（VPC）患者输注去氧肾上腺素。通过在输注前的心率水平进行心房起搏，探讨心率降低在抑制室性早搏中的作用。当观察到心率降低大于或等于20%时，认为压力感受器激活有效。10例患者（59%）达到目标心率降低（-29±5%），而7例（41%）患者的压力感受器反射被认为不足。在前一组（“反应者”）中，心率从73±7次/分钟降至52±6次/分钟（p<0.0001）。当心率允许波动时，10例患者中有9例的异位活动完全消失；室性早搏的平均数量从38±8次/100次心跳降至0.2±0.6次/100次心跳（p<0.0001）。在起搏期间，室性早搏再次出现，但其平均数量（22±10次/100次心跳）与对照值相比仍显著降低（p=0.003）。在“无反应者”中，尽管血压有适当升高，但室性早搏频率未受影响。在反应者组中，去氧肾上腺素输注期间QT间期延长（392±17毫秒），而对照条件下为（372±18毫秒，p=0.0008），而在无反应者中未观察到变化。这些结果表明，反射性迷走神经激活可显著减少室性早搏。这种作用仅部分依赖于心率；压力反射激活继发的直接和间接电生理变化也可能参与其中。
