Abstract
We report a case of external pacemaker malfunction analyzed by pacing system analyzer for complete atrio-ventricular block following mitral valve replacement and maze procedure. The malfunctions were inappropriate heart rate increase and marked bradycardia. The increase in heart rate resulted from safety pacing by crosstalk based on sensing of atrial pacing stimuli during ventricular refractory period. The bradycardia resulted from inhibition of ventricular pacing by crosstalk based on sensing of atrial pacing stimuli after ventricular refractory period. Hemodynamics was stable even during the malfunctions, because marked bradycardia was not sustained. The height of the crosstalk wave was higher than that of auto-atrial wave. Therefore, the atrial pacing output was decreased. The external pacemaker in postoperative cases with DDD pacing would be managed safely by using the pacing system analyzer for placement of epicardial leads.
