Influence of drive cycle length during programmed stimulation on induction of ventricular arrhythmias: analysis of 403 patients.

The drive cycle length at which programmed ventricular stimulation is performed is a fundamental variable in all stimulation protocols, but the influence of this variable on the ability to induce ventricular arrhythmias has not been systematically analyzed. This study, which included 403 patients with prior ventricular tachycardia (VT) or ventricular fibrillation undergoing programmed ventricular stimulation with a uniform protocol that incorporated 3 basic drive cycle lengths from the right ventricular apex, was performed to examine the influence of drive cycle length on the induction of ventricular arrhythmias. The sensitivity of the protocol was 62% for nonsustained VT, 73% for ventricular fibrillation and 89% for sustained VT. Fifty-four percent (217 patients) had an arrhythmia induced with programmed ventricular stimulation during ventricular pacing. No arrhythmia was induced in 96 patients (24%), whereas induction was accomplished during sinus rhythm in 61 patients (15%) and rapid ventricular pacing in 29 patients (7%). With this protocol, the sensitivity for single and double extrastimuli during ventricular pacing increases using decremental drive cycle lengths. Although only 2 patients had induction of a ventricular arrhythmia at a drive cycle length of 700 to 650 ms using a single extrastimulus, 14, 8 and 3 patients had ventricular arrhythmias induced by single extrastimuli at drive cycle lengths of 600 to 550, 500 to 450 and 400 ms, respectively. Of 163 patients with arrhythmias induced with double extrastimuli, only 6 had an arrhythmia induced at drive cycle lengths of 700 to 650 ms.(ABSTRACT TRUNCATED AT 250 WORDS)