Termination of ventricular tachycardia. Evaluation of a new pacing method.

Ventricular extrastimuli or rapid ventricular pacing used to terminate ventricular tachycardia (VT) may be ineffective or may accelerate VT. Therefore, a new method to facilitate termination of VT and decrease the incidence of acceleration was evaluated. The new method utilized rapid ventricular pacing at cycle length 10 to 100 ms shorter than VT cycle length with the introduction of 1 or 2 ventricular extrastimuli. The efficacy of this combination method in terminating VT was assessed in 25 patients in whom ventricular extrastimuli and rapid ventricular pacing at cycle lengths and coupling intervals comparable with those used in the new method were unsuccessful. This combination method successfully terminated VT in 21 of 25 patients with cycle lengths of 230 to 400 ms. VT was terminated in 6 of 8 patients receiving drugs in whom VT could not be terminated by 1 to 2 ventricular extrastimuli or rapid ventricular pacing; in 6 of 8 patients unresponsive to ventricular extrastimuli and in whom rapid ventricular pacing produced acceleration of VT; and in 9 of 9 patients in whom antiarrhythmic agents made VT unresponsive to ventricular extrastimuli or rapid ventricular pacing. A combination of rapid pacing and extrastimuli can terminate VT unresponsive to ventricular extrastimuli or rapid ventricular pacing alone and may avoid acceleration of VT using rapid ventricular pacing at very short cycle lengths for termination.