A seven-year-old male castrated Labrador Retriever presented emergently due to concern for pacemaker malfunction five years after successful transvenous pacemaker implantation to treat partial atrial standstill. On presentation, the dog's pulse rate was 30–50 beats per minute. An electrocardiogram showed no spontaneous atrial activity or paced ventricular activity. Pacemaker interrogation revealed an increased impedance of 7557 ohms, indicating a lead malfunction. Thoracic radiographs confirmed the lead was fractured and had excessive coiling. The transvenous pacing system was turned off, left in place, and an epicardial pacing system was implanted the following day. The dog was discharged with no perioperative complications. The dog eventually required escalated medical therapy for progressive cardiac disease and was euthanized two years after implantation of the replacement pacemaker. This manuscript illustrates a complete lead fracture and excessive lead coiling, which has not previously been detailed in veterinary medicine.

中文翻译：

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心血管图像：狗的起搏器引线断裂和过度卷绕

一只七岁的雄性拉布拉多猎犬在成功植入经静脉起搏器治疗部分心房停搏五年后，因担心起搏器故障而紧急就诊。就诊时，狗的脉搏率为每分钟 30-50 次。心电图显示无自发心房活动或起搏心室活动。起搏器询问显示阻抗增加至 7557 欧姆，表明导线出现故障。胸部X光片证实导线断裂且过度卷曲。关闭经静脉起搏系统，留在原处，并于第二天植入心外膜起搏系统。该犬出院，没有围手术期并发症。这只狗最终因进行性心脏病而需要升级药物治疗，并在植入替换起搏器两年后被安乐死。这份手稿说明了铅的完全断裂和铅的过度卷绕，这在兽医学中以前没有详细描述过。