Myopotential Interference with a DDD Pacemaker—Report of a Case

This case report describes myopotential interference with an automatic AV sequential pacemaker (DDD) producing repetitive firing of the ventricular channel up to a rate of 160 and occasional suppression of the ventricular output. A silastic boot which covered the pacemaker did not prevent sensing of electromyopotentials. The problem was partially corrected by decreasing the sensitivity of the ventricular channel. The ventricular response to myopotentials sensed by the atrial channel was limited by decreasing the maximum programmed rate to 120/minute.