IMPROVED DEFIBRILLATION THRESHOLDS WITH LARGE CONTOURED EPICARDIAL ELECTRODES AND BIPHASIC WAVE-FORMS
IMPROVED DEFIBRILLATION THRESHOLDS WITH LARGE CONTOURED EPICARDIAL ELECTRODES AND BIPHASIC WAVE-FORMS
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DOI：
10.1161/01.cir.76.5.1176
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发表时间：
1987-11-01
期刊：
影响因子：
37.8
通讯作者：
IDEKER, RE
中科院分区：
文献类型：
--
作者：
DIXON, EG;TANG, ASL;IDEKER, RE
减少除颤所需的电击强度将允许使用更小的自动植入式心律转复除颤器，并将减少休克引起心肌损伤的可能性。大多数内部除颤电极需要5到25 J才能成功地除颤于人类和狗。为了降低除颤所需的冲击强度，我们设计了两个大的钛除颤贴片电极，它们的形状适合于狗的右心室和左心室，分别覆盖大约33和39平方厘米的面积。在6只麻醉开胸犬中，电极直接固定在心外膜上，用60hz交流电诱发心室颤动。10秒后给予截断的指数单相和双相电击，测定去颤阈值（dft）。DFT为159 +-。48v, 3.2 .+-1.9 J（平均值）+。SD)用于10毫秒单相冲击和106。22v, 1.3 .+-。0.4 J，对于两相冲击，两相持续时间等于5毫秒（5-5毫秒）。在另外6只狗身上重复了这个实验，把电极固定在心包上。平均DFT不显著高于心外膜电极：165 +-。27 v, 3.1 .+-。1.2 J用于10毫秒单相冲击，116 .+。1.9 v, 1.6 +-。0.5 J用于5-5毫秒的双相冲击。低dft也获得双相冲击，其中第一阶段的持续时间比第二阶段的持续时间长。在第三组6只狗中，测定了大轮廓电极以及左右心外膜上10平方厘米的扁平贴片电极的dft。对于两种类型的波形，5-5毫秒双相波形的平均DFT明显低于10毫秒单相波形，并且对于两种类型的波形，大轮廓电极的平均DFT明显低于平坦贴片电极。我们得出结论，除颤所需的冲击强度可以通过双相冲击和大轮廓贴片电极显着降低。
A reduction in the shock strength required for defibrillation would allow use of a smaller automatic implantable cardioverter-defibrillator and would reduce the possibility of myocardial damage by the shock. Most internal defibrillation electrodes require 5 to 25 J for successful defibrillation in human beings and in dogs. In an attempt to lower the shock strength needed for defibrillation, we designed two large titanium defibrillation patch electrodes that were contoured to fit over the right and left ventricles of the dog heart, covering areas of approximately 33 and 39 cm2, respectively. In six anesthetized open-chest dogs, the electrodes were secured directly to the epicardium and ventricular fibrillation was induced by 60 Hz alternating current. Truncated exponential monophasic and biphasic shocks were given 10 sec later and debrillation thresholds (DFTs) were determined. The DFT was 159 .+-. 48 V, 3.2 .+-. 1.9 J (mean .+-. SD) for 10 msec monophasic shocks and 106 .+-. 22 V, 1.3 .+-. 0.4 J, for biphasic shocks with both phase durations equal to 5 msec (5-5 msec). The experiment was repeated in another six dogs in which the electrodes were secured to the pericardium. The mean DFT was not significantly higher than that for the electrodes on the epicardium: 165 .+-. 27 V, 3.1 .+-. 1.2 J for 10 msec monophasic shocks and 116 .+-. 19 V, 1.6 .+-. 0.5 J for 5-5 msec biphasic shocks. Low DFTs were also obtained with biphasic shocks in which the duration of the first phase was longer than that of the second. In a third group of six dogs, DFTs were determined for the large contoured electrodes as well as for 10 cm2 flat patch electrodes on the right and left ventricular epicardium. The mean DFT was significantly lower for the 5-5 msec biphasic waveform than for the 10 msec monophasic waveform for both types of electrodes and the mean DFT for the large contoured electrodes was significantly lower than that for the flat patch electrodes for both types of waveforms. We conclude that the shock strength required for defibrillation can be markedly lowered by means of biphasic shocks and large contoured patch electrodes.