Guarnieri T, Levine J H, Veltri E P, Griffith L S, Watkins L, Juanteguy J, Mower M M, Mirowski M
Johns Hopkins University School of Medicine, Baltimore, Maryland.
Am J Cardiol. 1987 Nov 1;60(13):1061-4. doi: 10.1016/0002-9149(87)90352-3.
Because the automatic internal cardioverter defibrillator's long-term ability to reduce arrhythmic mortality in patients with ventricular tachycardia/fibrillation is unknown, it is important to determine whether the threshold for defibrillation changes over time. Serial defibrillation thresholds were measured in 23 patients over a mean replacement time of 24.8 +/- 7.5 months. In all cases the lead system was a superior vena cava coil to a left ventricular epicardial patch. The defibrillation threshold for the entire group increased from 12.3 +/- 4.7 J to 16.9 +/- 5.9 J (p less than 0.05). Striking increases in the defibrillation threshold were seen in the subgroup of patients taking amiodarone (from 10.9 +/- 4.3 J at implantation to 20.0 +/- 4.7 J at replacement, p less than 0.05). Defibrillation threshold decreased in patients taking no antiarrhythmic drugs or taking class I agents. Thus, the increase in mean defibrillation threshold was the result of an increase in the patients taking amiodarone. These data suggest that at initial implantation lead systems associated with the lowest defibrillation threshold should be used and the defibrillation threshold should be measured at generator change to guarantee an adequate margin of safety.
由于自动体内心脏复律除颤器降低室性心动过速/心室颤动患者心律失常死亡率的长期能力尚不清楚，因此确定除颤阈值是否随时间变化很重要。在23例患者中，平均更换时间为24.8±7.5个月，测量了连续的除颤阈值。在所有病例中，导联系统均为上腔静脉线圈至左心室心外膜补片。整个组的除颤阈值从12.3±4.7 J增加到16.9±5.9 J（p<0.05）。服用胺碘酮的患者亚组中，除颤阈值显著升高（从植入时的10.9±4.3 J增加到更换时的20.0±4.7 J，p<0.05）。未服用抗心律失常药物或服用I类药物的患者除颤阈值降低。因此，平均除颤阈值的升高是服用胺碘酮患者增加的结果。这些数据表明，在初始植入时应使用与最低除颤阈值相关的导联系统，并在更换发生器时测量除颤阈值，以确保有足够的安全余量。
