Ujhelyi M R, Schur M, Frede T, Gabel M, Markel M L
University of Georgia College of Pharmacy, Augusta, USA.
Circulation. 1995 Sep 15;92(6):1644-50. doi: 10.1161/01.cir.92.6.1644.
Defibrillation waveforms and antiarrhythmic drugs have disparate effects on myocardial excitability and refractoriness, making it likely that antiarrhythmic drugs will interact with one waveform differently than with another. The aim of the present study was to determine if the increase in defibrillation threshold (DFT) induced by lidocaine is similar for electrical shocks with monophasic and biphasic waveforms.
Twenty-six pentobarbital-anesthetized farm-raised pigs were instrumented with pacing catheters and epicardial defibrillation electrodes. Each pig was assigned to one of four groups: (1) monophasic shock waveform and placebo (5% dextrose in water [D5W]) (n = 7), (2) monophasic shock waveform and lidocaine (n = 7), (3) biphasic shock waveform and placebo (D5W) (n = 5), or (4) biphasic shock waveform and lidocaine (n = 7). DFT was measured at baseline and subsequently during treatment (D5W or lidocaine). In the monophasic waveform groups, DFT increased from baseline in response to lidocaine by 92% (P < .0001), whereas DFT values in response to D5W did not change. In the biphasic waveform groups, DFT values did not change from baseline in response to lidocaine (P = NS), whereas DFT values from baseline in response to D5W significantly decreased by 29% (P = .04). In the monophasic waveform groups, the change in DFT from baseline in response to lidocaine was significantly different than the change from baseline in response to D5W (92 +/- 29% versus -0.5 +/- 29%, respectively) (P < .0002). In the biphasic waveform groups, however, the change in DFT from baseline in response to lidocaine was similar to the change from baseline in response to D5W (-5.66 +/- 15% versus -29 +/- 17%, respectively) (P = .48). Furthermore, the change in DFT from baseline in response to lidocaine differed significantly between monophasic and biphasic waveform groups (92 +/- 29% versus -5.66 +/- 15%) (P < .0002), whereas the change from baseline in response to D5W did not differ between monophasic and biphasic waveforms (-0.5 +/- 29% versus -29 +/- 17%) (P = .34).
Compared with placebo groups, DFT values increased during lidocaine treatment to a much greater degree in the monophasic waveform group than in the biphasic waveform group receiving lidocaine. These data support our hypothesis that antiarrhythmic drugs can affect the defibrillation efficacy of monophasic waveforms differently than that of biphasic waveforms.
除颤波形与抗心律失常药物对心肌兴奋性和不应期有不同影响，这使得抗心律失常药物与一种波形相互作用的方式可能不同于另一种波形。本研究的目的是确定利多卡因引起的除颤阈值（DFT）升高对于单相和双相波形电击是否相似。
26只戊巴比妥麻醉的农场饲养猪被植入起搏导管和心外膜除颤电极。每只猪被分配到四组之一：（1）单相电击波形和安慰剂（5%葡萄糖水溶液[D5W]）（n = 7），（2）单相电击波形和利多卡因（n = 7），（3）双相电击波形和安慰剂（D5W）（n = 5），或（4）双相电击波形和利多卡因（n = 7）。在基线时以及随后治疗期间（D5W或利多卡因）测量DFT。在单相波形组中，利多卡因使DFT从基线升高92%（P <.0001），而D5W使DFT值无变化。在双相波形组中，利多卡因使DFT值与基线相比无变化（P =无显著性差异），而D5W使DFT值从基线显著降低29%（P =.04）。在单相波形组中，利多卡因使DFT相对于基线的变化显著不同于D5W使DFT相对于基线的变化（分别为92±29%对-0.5±29%）（P <.0002）。然而，在双相波形组中，利多卡因使DFT相对于基线的变化与D5W使DFT相对于基线的变化相似（分别为-5.66±15%对-29±17%）（P =.48）。此外，单相和双相波形组中利多卡因使DFT相对于基线的变化有显著差异（92±29%对-5.66±15%）（P <.0002），而D5W使DFT相对于基线的变化在单相和双相波形之间无差异（-0.5±29%对-29±17%）（P =.34）。
与安慰剂组相比，利多卡因治疗期间单相波形组的DFT值升高程度远大于接受利多卡因的双相波形组。这些数据支持我们的假设，即抗心律失常药物对单相波形除颤疗效的影响与双相波形不同。
