Pacemaker malfunction.

The field of cardiac pacing has expanded rapidly in recent years. Engineering improvements and microprocessor technology have resulted in a vast increase in pacemaker technology. The "high-tech" edge of cardiac pacing often discourages all but the pacemaker specialist from approaching a malfunctioning pacemaker. Electrocardiographic signs of pacemaker malfunction can be grouped into four categories: failure to output, failure to capture, undersensing, and inappropriate pacemaker rate. For each of these categories, there may be true malfunctions and pseudomalfunctions. In addition, environmental sources of electromagnetic interference, both within and outside the hospital environment, can result in pacemaker malfunction. Approaching pacemaker malfunction with these categories in mind should help minimize confusion.