Tisdale J E, Shimoyama H, Sabbah H N, Webb C R
College of Pharmacy and Allied Health Professions, Wayne State University, Detroit, MI 48202, USA.
Pharmacotherapy. 1996 May-Jun;16(3):429-37.
We determined the effect of cocaine on ventricular vulnerability to fibrillation, as measured by ventricular fibrillation threshold (VFT), and cardiac electrophysiology in 20 anesthetized dogs with normal hearts. Animals were randomized in blinded fashion to receive a continuous 3-hour infusion of cocaine 0.11 mg/kg/minute (total dose 20 mg/kg) or placebo (lactose dissolved in normal saline). The VFT, systolic and diastolic blood pressures, ventricular effective refractory period (ERP), and electrocardiographic intervals were measured at baseline and every 30 minutes during infusion. Baseline mean +/- SE VFT in cocaine and placebo groups was 57.0 +/- 7.8 and 51.8 +/- 7.6 mA, respectively (p = 0.64). Cocaine did not significantly decrease VFT, but actually increased it (i.e., reduced ventricular vulnerability to fibrillation) compared with placebo (84.6 +/- 10.4 vs 55.8 +/- 7.2 mA, respectively, at 150 minutes, p = 0.04). Cocaine prolonged ERP and PR, QRS, QT, QTc, JT, and JTc intervals. Cocaine does not increase ventricular vulnerability to fibrillation in anesthetized dogs with normal intact hearts. Its electrophysiologic effects are similar to those of class I antiarrhythmic agents in this model.
我们测定了可卡因对正常心脏的20只麻醉犬心室颤动易感性的影响（通过心室颤动阈值（VFT）衡量）以及心脏电生理。动物被随机分组，以盲法接受持续3小时的可卡因输注，剂量为0.11 mg/kg/分钟（总剂量20 mg/kg）或安慰剂（溶解于生理盐水中的乳糖）。在输注前的基线以及输注期间每30分钟测量VFT、收缩压和舒张压、心室有效不应期（ERP）以及心电图间期。可卡因组和安慰剂组的基线平均±标准误VFT分别为57.0±7.8和51.8±7.6 mA（p = 0.64）。与安慰剂相比，可卡因并未显著降低VFT，实际上还使其升高了（即降低了心室颤动易感性）（分别在150分钟时为84.6±10.4和55.8±7.2 mA，p = 0.04）。可卡因延长了ERP以及PR、QRS、QT、QTc、JT和JTc间期。在正常完整心脏的麻醉犬中，可卡因不会增加心室颤动易感性。在该模型中，其电生理效应与I类抗心律失常药物相似。
