Case 77

Abstract

A 63-year-old woman with paroxysmal atrial fibrillation and rapid ventricular response and intermittent presyncope is found to have symptomatic sinus pauses >3 s on Holter monitoring as well as an intermittent accelerated junctional rhythm. In sinus rhythm, her PR interval is 180 ms, and she has normal QRS complex morphology. She undergoes placement of a St. Jude Identity ADx dual chamber pacemaker without any apparent complications. Notably, the majority of the right atrial sites tested for capture and sensing thresholds exhibited low intracardiac voltage, and an acceptable atrial sensitivity could be achieved only in the low right atrium. © Springer-Verlag London Limited 2011.