Reversible atrial fibrillation following Crotalinae envenomation

Abstract Background Cardiotoxicity is a documented complication of Crotalinae envenomation. Reported cardiac complications following snake envenomation have included acute myocardial infarction, electrocardiogram abnormalities and arrhythmias. Few reports exist describing arrhythmia induced by viper envenomation and to our knowledge none describe arrhythmia induced by Crotalinae envenomation. This report concerns the first known case of atrial fibrillation precipitated by rattlesnake bite. Case presentation A 73-year-old Caucasian man with a past medical history of hypertension, hyperlipidemia, type 1 diabetes mellitus, and a baseline first-degree atrioventricular block presented to the emergency department following a rattlesnake bite to his left lower leg. He developed pain and swelling in his left leg two-hour post-envenomation and subsequently received four vials of Crotalidae polyvalent immune fab (ovine). At three-hour post-envenomation following transfer to the intensive care unit, an electrocardiogram revealed new-onset atrial fibrillation. An amiodarone drip was started and the patient successfully converted to normal sinus rhythm approximately six hours after he was found to be in atrial fibrillation. A transthoracic echocardiogram revealed mild concentric left ventricular hypertrophy and an ejection fraction of 72%. He was discharged the following day with no hematological abnormalities and a baseline first-degree atrioventricular block. Conclusion This is the first documented case of reversible atrial fibrillation precipitated by Crotalinae envenomation. In patients with pertinent risk factors for developing atrial fibrillation, physicians should be aware of the potential for this arrhythmia. Direct toxic effects of venom or structural and electrophysiological cardiovascular abnormalities may predispose snakebite patients to arrhythmia, warranting extended and attentive cardiac monitoring.

【摘要】
背景：蝰亚科（Crotalinae）蛇咬伤中毒可引发心脏毒性，这是已获证实的临床并发症。既往关于蛇咬伤中毒所致心脏并发症的报道包括急性心肌梗死、心电图（electrocardiogram）异常及心律失常。目前鲜有关于蝰科蛇毒中毒诱发心律失常的相关报道，据我们所知，尚无针对蝰亚科蛇毒中毒诱发心律失常的病例描述。本报告为首例经证实的响尾蛇咬伤诱发心房颤动的临床病例。

病例报告：1例73岁白人男性患者，既往有高血压、高脂血症、1型糖尿病病史，基线心电图提示一度房室传导阻滞（first-degree atrioventricular block），因左下肢被响尾蛇咬伤前往急诊科就诊。中毒后2小时，患者左下肢出现疼痛与肿胀，随后接受了4瓶多价蝰科蛇毒免疫Fab（羊源）（Crotalidae polyvalent immune fab (ovine)）制剂治疗。转至重症监护室后，于中毒后3小时行心电图检查，提示新发心房颤动。随即启动胺碘酮（amiodarone）静脉滴注，患者在确诊心房颤动约6小时后成功转复为窦性心律。经胸超声心动图（transthoracic echocardiogram）检查显示轻度向心性左心室肥厚，射血分数（ejection fraction）为72%。次日患者出院，未出现血液系统异常，基线仍为一度房室传导阻滞。

结论：本报告为首例经证实的蝰亚科蛇毒中毒诱发可逆性心房颤动的临床病例。对于存在心房颤动相关危险因素的患者，临床医师应警惕此类心律失常的发生风险。蛇毒的直接毒性作用，或心血管系统结构与电生理异常，可能使蛇咬伤患者易于出现心律失常，因此需对患者进行延长且细致的心脏监测。