Gliner B E, Murakawa Y, Thakor N V
Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland.
Pacing Clin Electrophysiol. 1990 Mar;13(3):326-38. doi: 10.1111/j.1540-8159.1990.tb02046.x.
The effect of applying an energy pulse to the heart during ventricular fibrillation is described by the probability of successful defibrillation or success rate. Seven to ten (8.60 +/- 0.84: mean +/- standard deviation) defibrillation trials per energy were randomly attempted at energies which span the defibrillation success rate versus energy curve. We obtained 70.0 +/- 8.4 episodes per dog. We fit the defibrillation success rate versus energy relationship from ten dogs (20.5 +/- 1.5 kg) to four types of curves: linear, exponential, probit transformed linear, and logit transformed linear. The correlation coefficients for each fit are 0.917 +/- 0.057, 0.944 +/- 0.014, 0.926 +/- 0.51, and 0.889 +/- 0.098, respectively. We therefore conclude that the exponential curve best describes the DSRE relationship. This suggests the existence of an energy below which defibrillation does not occur. At higher energies, the exponential curve asymptotically approaches a 100% success rate, which indicates that increasing the energy produces a diminishing benefit to defibrillation success rate. The estimated energies with a 0% defibrillation success rate are surprisingly consistent among dogs, with 2.072 +/- 0.553 J. The estimated energy with an 80% defibrillation success rate is 5.217 +/- 1.091 J. The estimated defibrillation success rate corresponding to the defibrillation threshold of 3.59 +/- 1.06 J is consistent with 0.516 +/- 0.144. The estimated energies with a 0% success rate correlate well with the defibrillation thresholds with R = 0.772; P = 0.0088. Since implantable defibrillators have a limited energy supply, we determined energy efficiency by dividing defibrillation success rate by the applied energy and energy consumption by dividing the applied energy by the defibrillation success rate. The most efficient defibrillation energy occurs at the maximum energy efficiency and the minimum energy consumption. The most efficient defibrillation energy of 4.34 +/- 0.97 J determined from the exponential fit has a success rate of 0.70 +/- 0.06. The most efficient defibrillation energy can be predicted from the defibrillation threshold. Clinically, a 70% success rate may not be adequate. We, therefore, compared the energy efficiency and consumption of energies with 90% and 95% success rates to the most efficient defibrillation energy. About a 50% increase in energy from the most efficient defibrillation energy is necessary for a 90% success rate which results in about a 13% loss in energy efficiency and about a 16% increase in energy consumption. About an 84% energy increase is necessary for a 95% success rate which results in about a 24% loss in energy efficiency and about a 33% increase in energy consumption.(ABSTRACT TRUNCATED AT 400 WORDS)
通过成功除颤的概率或成功率来描述在心室颤动期间对心脏施加能量脉冲的效果。在跨越除颤成功率与能量曲线的能量水平下，每种能量随机尝试进行7至10次（8.60±0.84：均值±标准差）除颤试验。我们每只狗获得70.0±8.4次发作。我们将来自10只狗（20.5±1.5千克）的除颤成功率与能量关系拟合为四种类型的曲线：线性、指数、概率单位变换线性和对数单位变换线性。每种拟合的相关系数分别为0.917±0.057、0.944±0.014、0.926±0.51和0.889±0.098。因此，我们得出结论，指数曲线最能描述除颤成功率与能量关系（DSRE关系）。这表明存在一个能量阈值，低于该阈值除颤不会发生。在较高能量下，指数曲线渐近地接近100%的成功率，这表明增加能量对除颤成功率的益处逐渐减小。在狗之间，估计的除颤成功率为0%时的能量惊人地一致，为2.072±0.553焦耳。估计的除颤成功率为80%时的能量为5.217±1.091焦耳。对应于3.59±1.06焦耳除颤阈值的估计除颤成功率为0.516±0.144。估计的除颤成功率为0%时的能量与除颤阈值的相关性良好，R = 0.772；P = 0.0088。由于植入式除颤器的能量供应有限，我们通过将除颤成功率除以施加的能量来确定能量效率，并通过将施加的能量除以除颤成功率来确定能量消耗。最有效的除颤能量出现在最大能量效率和最小能量消耗处。根据指数拟合确定的最有效的除颤能量为4.34±0.97焦耳，成功率为0.70±0.06。最有效的除颤能量可以从除颤阈值预测。临床上，70%的成功率可能不够。因此，我们将成功率为90%和95%时的能量效率和能量消耗与最有效的除颤能量进行了比较。要达到90%的成功率，需要比最有效的除颤能量增加约50%的能量，这会导致能量效率损失约13%，能量消耗增加约16%。要达到95%的成功率，需要增加约84%的能量，这会导致能量效率损失约24%，能量消耗增加约33%。（摘要截断于400字）
