Rib Perforation From a Right Ventricular Pacemaker Lead
A 50-year-old man was admitted to a community hospital for high fever. Seven years earlier, he had been in a motor vehicle accident and a cervical spine injury had resulted in quadriplegia and ventilator dependence. During that hospitalization, he was noted to have long sinus pauses that were thought to be vagally mediated, and a single-chamber pacemaker was implanted to hasten his recovery, with an active fixation pacing lead placed at the right ventricular apex (Figure 1A through 1C). His bradycardia spells subsequently disappeared, and minimal pacing was needed.
Because of spiking fevers, leukocytosis, and methicillin-resistent Staphylococcus aureus growing from blood cultures; a chest x-ray (Figure 1D) and a chest computed tomography scan (Figure 2) were performed. Neither revealed any obvious source of infection, but his ventricular pacing lead had perforated through the right ventricular apex, with the lead tip now sitting in soft tissue just outside the rib cage near the seventh rib.
Although it was not clear whether the pacemaker lead was infected in either its intravascular or extracardiac course, it was decided that the lead should be removed to avoid future mechanical complications at the least. The patient was referred for surgical pacemaker-system extraction. In the operating room, chest wall exploration revealed ventricular lead penetration through the seventh rib (Figure 3A). Local granulation tissue and a short segment of the perforated rib were resected (Figure 3B) and sent for culture. The lead was disconnected from the right pectoral pacemaker generator, and manual traction was used to free the lead from intravascular binding sites. The apical defect in the right ventricle was closed with a purse-string suture. There was no evidence of bleeding or cardiac tamponade. The excised granulation tissue and rib fragment did not reveal bacteria on Gram’s stain, and tissue cultures showed no growth. The patient recovered well, with resolution of bacteremia after removal of an indwelling intravenous catheter and a course of antibiotics.
This case illustrates the unusual complication of a delayed pacemaker lead perforation with erosion through bone. Myocardial perforation with pericardial effusion and cardiac tamponade is a short-term complication of pacemaker implantation in 1% of patients.1 Late perforation of pacemaker leads is far less common, with a variety of time frames, symptoms, and clinical findings reported.2–7 The clinical presentation may include extracardiac muscle stimulation, pericardial tamponade, chest pain, or even incidental discovery during an imaging procedure, as in the current case.
If the perforated lead is to be percutaneously extracted, there must be extreme vigilance for the possible development of pericardial effusion and cardiac tamponade after the lead is withdrawn. Such procedures are best performed in an operating room setting under general anesthesia with transesophageal echocardiography, where close monitoring and rapid surgical rescue is possible. If the lead tip has migrated beyond the pericardium, referral for surgical extraction is the safest option, with the ability to directly visualize and repair the site of perforation and to deal with injury to adjacent structures.
Because late lead perforations are quite rare, the predisposing factors are not well understood. Low-profile leads might pose an increased risk for perforation because there would be a higher force per unit area at the lead tip compared with a larger-caliber lead. Active fixation leads are more commonly reported to cause late perforation. Forces at the lead tip are complex, vary during the cardiac cycle, and may change over time. The interplay between longitudinal forces along the lead tip and the ability of the local myocardium to withstand those forces will result in either lead stability or lead perforation, with the former predominating in the vast majority of cases. Lead positioning plays a role, with placement on the interventricular septum likely posing less risk than implantation in the right ventricular apex or free wall.