Watanabe Ichiro, Okumura Yasuo, Nagashima Koichi, Kofune Masayoshi, Ohkubo Kimie, Mano Hiroaki, Sonoda Kazuyuki, Kasamaki Yuji, Hirayama Atsushi
Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
Int Heart J. 2012;53(3):187-92. doi: 10.1536/ihj.53.187.
Adenosine and related compounds have been shown to produce atrioventricular (AV) conduction block during acute myocardial ischemia. We investigated the effects of the antianginal drug trapidil, which has been shown to inhibit phosphodiesterase, on AV conduction disturbances in a canine model of acute myocardial ischemia. In 35 anesthetized dogs, the AV node artery was cannulated and perfused with arterial blood. Adenosine (300 µg, 650 µg, or 1000 µg) was injected into the AV node artery. With administration of adenosine at 300 µg, 650 µg, or 1000 µg, the atrio-His (AH) interval was increased by 14.6 ms, 22.3 ms, and 29.7 ms, respectively. The effects of adenosine were potentiated by pretreatment with intravenous dipyridamole (250 µg/kg), an inhibitor of adenosine uptake, but the effects of adenosine were attenuated with intravenous trapidil (3 mg/kg), an inhibitor of phosphodiesterase. AV node artery occlusion resulted in prolongation of the AH interval in 4 of 12 dogs. The ischemia-induced AH prolongation was potentiated with intravenous dipyridamole and attenuated with intravenous trapidil. AV conduction disturbances associated with inferior myocardial infarction may be related in part to endogenously released adenosine, and trapidil may be useful in treating AV block associated with acute AV node ischemia.
腺苷及相关化合物已被证明在急性心肌缺血期间会导致房室（AV）传导阻滞。我们研究了抗心绞痛药物曲匹地尔（已证明其可抑制磷酸二酯酶）对急性心肌缺血犬模型中房室传导障碍的影响。在35只麻醉犬中，将房室结动脉插管并用动脉血灌注。向房室结动脉注射腺苷（300μg、650μg或1000μg）。分别给予300μg、650μg或1000μg腺苷时，心房-希氏束（AH）间期分别增加14.6毫秒、22.3毫秒和29.7毫秒。静脉注射双嘧达莫（250μg/kg，一种腺苷摄取抑制剂）预处理可增强腺苷的作用，但静脉注射曲匹地尔（3mg/kg，一种磷酸二酯酶抑制剂）可减弱腺苷的作用。房室结动脉闭塞导致12只犬中有4只的AH间期延长。静脉注射双嘧达莫可增强缺血诱导的AH间期延长，而静脉注射曲匹地尔可使其减弱。与下壁心肌梗死相关的房室传导障碍可能部分与内源性释放的腺苷有关，曲匹地尔可能对治疗与急性房室结缺血相关的房室传导阻滞有用。
