Entrainment of ventricular tachycardia in postoperative tetralogy of Fallot.
The mechanism of ventricular tachycardia (VT) in postoperative tetralogy of Fallot has been ascribed to both reentry and triggered automaticity. We performed electrophysiologic studies on a patient with this condition and induced sustained uniform ventricular tachycardia by programmed extrastimulation. Pacing during the tachycardia at multiple cycle lengths from the right ventricular apex (RVA) and outflow tract (RVOT) produced constant but progressive fusion between the paced and tachycardia QRS. With termination of pacing, the last captured complex was unfused but coupled at the paced cycle length and then the tachycardia resumed at its intrinsic rate. Therefore, the VT was entrained. In addition, an area of slow conduction between the RVOT and RVA was demonstrated. These findings support a reentrant mechanism of this arrhythmia.
Kremers
M S
MS
Cardiology Division, University of Texas Southwestern Medical Center, Dallas 75235-9034.
Wells
P J
PJ
Black
W H
WH
Solodyna
M A
MA
D000328:Adult; D002037:Bundle-Branch Block / Q000209:etiology; D005117:Cardiac Complexes, Premature / Q000209:etiology; D002304:Cardiac Pacing, Artificial; D005260:Female; D006801:Humans; D013610:Tachycardia / Q000209:etiology* / Q000628:therapy; D013771:Tetralogy of Fallot / Q000150:complications / Q000601:surgery*