Pacemakers are frequently implanted, yet accurate prospective data on implant complications are limited. Elderly patients may be at increased risk of implant complications and are increasingly being referred for pacemaker implantation. The purpose of the present analysis was to define the incidence and possible predictors of serious complications of dual chamber permanent pacemaker implantation in the elderly. Therefore, we sought to prospectively identify the incidence and predictors of pacemaker implant complications in a large multicenter trial involving patients receiving a dual chamber pacemaker. The Pacemaker Selection in the Elderly (PASE) study was a prospective trial designed to evaluate quality of life in dual chamber pacemaker recipients age 65 years or older randomized to DDDR versus VVIR programming. In addition to being age 65 years or older, patients enrolled in this study were in normal sinus rhythm, and had standard indications for permanent pacemaker implantation. All patients received dual chamber pacemakers and were randomized to DDDR versus VVIR pacing. Pacemaker implant complications were collected on standardized forms which were completed at pacemaker implantation and during follow-up appointments. In this study of 407 patients, there were 26 complications occurring in 25 patients (6.1%). The most frequent complication was lead dislodgment which occurred in 9 patients. This was followed by pneumothorax (8 patients) and cardiac perforations (4 patients). In 18 patients (4.4%) repeat surgical procedures (including chest tubes) were required. Complications were noted prior to discharge in only 18 patients. There were no significant predictors of overall complications. Pneumothorax was more frequent in patients > or = 75 years old, and was observed only in patients with subclavian venous access. In conclusion, complications from pacemaker implantation in the elderly are seen in 6.1% of patients and 4.4% of patients require a repeat surgical procedure. Other than advanced age and lower weight predicting for pneumothorax, there are no significant clinical predictors of complications.