Automatically optimizing pacing output: an excellent idea, but with potentially lethal pitfalls.

AutoCapture (AC) and Ventricular Capture Management (VCM) are pacing algorithms that attempt to automatically optimize pacing output, providing consistent capture and enhancing device longevity. This report describes potentially serious consequences from use of these algorithms. In one pacemaker dependent patient, AC malfunction led to failure of ventricular capture. This was fixed with a software correction. The potential seriousness of AC malfunction leads to the recommendation that this software be downloaded into all susceptible pacemakers. In a second patient, VCM malfunction resulted in unnecessary high output pacing. Our experience illustrates the need for postmarketing surveillance when embracing newer technology.