%0 Journal Article %A D. C. Lefroy %A T. Crake %A D. W. Davies %T Ventricular tachycardia: an unusual pacemaker-mediated tachycardia. %D 1994 %R 10.1136/hrt.71.5.481 %J British Heart Journal %P 481-483 %V 71 %N 5 %X A 74 year old man had recurrent ventricular tachycardia, which was well controlled with amiodarone, and complete heart block for which a VVI permanent pacing system had previously been implanted. After an elective increase in the programmed pacemaker rate from 70 to 82 beats/min, there was recurrence of frequent episodes of ventricular tachycardia. Each episode of tachycardia was initiated by a fusion beat consisting of a ventricular extrasystole and a paced beat. When the pacemaker rate was reprogrammed to 70 beats/min the episodes of tachycardia ceased abruptly. It is proposed that the fusion of a ventricular extrasystole with a pacemaker beat may have induced ventricular tachycardia, even though neither of these beats occurring separately was sufficient to cause this. %U https://heart.bmj.com/content/heartjnl/71/5/481.full.pdf