Ventricular tachycardia: an unusual pacemaker-mediated tachycardia.
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.
Lefroy
D C
DC
Department of Cardiac Medicine, National Heart and Lung Institute, London.
Crake
T
T
Davies
D W
DW
D000368:Aged; D004562:Electrocardiography; D006321:Heart / Q000503:physiopathology; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000503:physiopathology