Murakawa Y, Gliner B E, Thakor N V
Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205.
Am Heart J. 1989 Sep;118(3):451-8. doi: 10.1016/0002-8703(89)90257-3.
To determine the temporal profile of the energy requirement for defibrillation, shocks were delivered to canine hearts after 5, 10, or 20 seconds from the onset of fibrillation with a combination of patch and catheter electrodes. A total of 956 fibrillation-defibrillation sequences were performed at one of four energy levels appropriately selected for each period of fibrillation in 10 anesthetized dogs. The energy values related to 50% (E50) and 80% (E80) of the predicted success were calculated from a logistic regression curve. The E50 and E80 values at 10 seconds after the onset of fibrillation were less than those at 20 seconds after the onset by 7.1% +/- 18.3% and 9.7% +/- 21.4%, respectively; differences were not significant. At 5 seconds after the onset, the differences were 15.3% +/- 14.2% (p less than 0.02) and 16.4% +/- 12.7% (p less than 0.01), respectively. The defibrillation energy efficiency was assessed by dividing the success rate (SR) of fibrillation by the applied energy (E). The maximal SR/E at 5, 10, and 20 seconds of fibrillation was achieved at the energy corresponding to the SRs of 88.8% +/- 4.5%, 90.4% +/- 3.9%, and 88.1% +/- 4.6%, respectively. We conclude that the energy requirement for defibrillation increases with the duration of fibrillation, even shortly after the onset of fibrillation, and the maximal energy efficiency is attained at the energy associated with the SR of approximately 90%.
为了确定除颤所需能量的时间分布情况，在10只麻醉犬的心脏发生颤动5、10或20秒后，使用贴片电极和导管电极组合进行电击除颤。在每个颤动时间段，从四个适当选择的能量水平之一对10只麻醉犬总共进行了956次颤动-除颤序列操作。根据逻辑回归曲线计算出与预测成功率的50%（E50）和80%（E80）相关的能量值。颤动开始后10秒时的E50和E80值分别比开始后20秒时低7.1%±18.3%和9.7%±21.4%；差异不显著。在颤动开始后5秒时，差异分别为15.3%±14.2%（p<0.02）和16.4%±12.7%（p<0.01）。除颤能量效率通过将颤动成功率（SR）除以施加能量（E）来评估。在颤动5、10和20秒时，最大SR/E分别在对应成功率为88.8%±4.5%、90.4%±3.9%和88.1%±4.6%的能量水平下实现。我们得出结论，即使在颤动开始后不久，除颤所需能量也会随着颤动持续时间的增加而增加，并且在与约90%的成功率相关的能量水平下可达到最大能量效率。
