Chest Pain Associated with Moderator Band Pacing

Abstract

T ransvenous pacing with an implanted pacemaker has become the treatment of choice for cardiac rhythm disturbances such as sinus node dysfunction and complete heart block.1-5 Transvenous pacing leads are inserted with fluoroscopic guidance and positioned in the right atrium and right ventricle (RV). In most patients, the right atrial appendage is the optimal location for the right atrial lead. However, the optimal position of the RV lead varies in accordance with RV anatomy (dimensions and orientation of the RV in the thorax), the presence of tricuspid regurgitation or cardiomyopathy, the patient's history of infarction, and the operator's experience. After pacemaker placement, ventricular cardiac pacing stimuli might cause acute or chronic chest pain, which usually is associated with cardiac perforation that requires emergency evaluation and treatment. 6 We treated a patient who had chronic chest pain associated with placement of the RV lead in a calcified moderator band. We discuss the treatment and results. Case ReportA 65-year-old man was evaluated because of chronic chest pain. His medical history included inducible ventricular tachycardia, which had been treated 8 years earlier with a dual-chamber implantable cardioverter-defibrillator (ICD). The right atrial lead was model 4470, and the RV lead was model 0185 of the Endotak Reliance ® G (Boston Scientific Corporation; Natick, Mass).At the time of ICD implantation, the patient had been treated with sotalol; a coronary angiogram had shown nonobstructive coronary artery disease and a left ventricular ejection fraction of 0.45 to 0.50, consistent with mild idiopathic nonischemic cardiomyopathy. The chest pain had begun after implantation of the ICD and had persisted until his current presentation, 8 years later. The patient's medical history was also notable for hypertension, severe emphysematous chronic obstructive pulmonary disease, esophageal stricture (previously treated with dilation), and stroke. His body mass index was 23 kg/m 2 . We determined that the patient needed elective replacement of the ICD generator. He reported a chronic poking sensation in the chest, which was reproduced at the minimum RV pacing threshold, but not by manipulating the ICD pulse-generator pocket. He tolerated atrial pacing well and had no chest pain during high-rate atrial pacing. There was normal lead-integrity response to both left pectoral muscle isomet-

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