Runaway Pacemaker A Persisting Problem

Abstract

RECENT literature suggests that pacemaker tachycardia or runaway has become a rare problem. The phenomenon still occurs, however, and may be transient and difficult to document. Report of a Case An 85-year-old woman was brought to the emergency room after collapsing at home. She had had a Stanicor model 143 E7 ventricular inhibited pacer inserted transvenously at another hospital 261 days earlier for complete heart block with a slow ventricular rate. Her symptoms prior to the insertion were fatigue, lethargy, and syncope, as well as an episode of cerebral vascular insufficiency with transient left-sided weakness and dysarthria. She subsequently did well until the morning of admission, when she suddenly collapsed. In the emergency room the patient was unresponsive and apneic, and her blood pressure was unobtainable. An electrocardiogram demonstrated the pacemaker artifact at a variable rate between 300 to 375 beats per minute (Figure). There was no sign of ventricular