RESUMO
A 5-year-old short-haired dachshund was referred with a history of repeated syncope associated with a third-degree atrioventricular block. A permanent transvenous pacemaker with an active-fixation lead was implanted. In the following 3 weeks, the syncopal episodes reappeared owing to a loss of ventricular capture. The pacemaker was reprogrammed to higher output, and effective pacing was re-established. Thoracic radiographs and echocardiography failed to identify any evidence of lead displacement. One month later, the patient presented a new episode of loss of capture. After fluoroscopy, cardiac perforation was suspected and subsequently confirmed by thoracotomy. An epicardial pacemaker lead was implanted without removing the perforating lead as there were no bleeding complications or damage to adjacent organs, and the length of time elapsed since implantation was assumed to have allowed for significant fibrotic adhesions to develop. Nineteen months after epicardial pacemaker implantation, endocardial lead dislodgement occurred. Simultaneously, the dog presented with gastrointestinal and respiratory abnormalities and severe thrombocytopenia. Once the dog was stabilized, the endocardial lead was percutaneously removed. One month later, loss of ventricular capture recurred. The owners declined any further treatment, and euthanasia was elected. Cardiac perforation after pacemaker implantation is an infrequent complication. In this case, the dog lived 22 months after subacute right ventricular perforation. Despite the poor prognosis associated with cardiac perforation by pacemaker leads, different approaches are possible to successfully manage this major complication. Extraction of the displaced lead remains controversial as, if the lead is not removed, late lead migration can occur.