Right ventricular triple extrastimuli induced tachycardia in 46% of patients presenting with cardiac arrest compared to 22% of those with stable sustained ventricular tachycardia (p<0.001).
Observational (n=243)
Does the use of triple extrastimuli during electrophysiologic study affect the induction of ventricular tachyarrhythmias in patients with and without documented sustained ventricular tachyarrhythmias?
Triple extrastimuli during electrophysiologic studies frequently induce polymorphic and nonsustained tachycardias in patients without spontaneous arrhythmias, and induce faster tachycardias in cardiac arrest survivors compared to those with stable ventricular tachycardia.
Absolute Event Rate: 46% vs 22%
p-value: p=<0.001
Electrophysiologic studies were performed in 172 consecutive patients for evaluation of documented sustained ventricular tachyarrhythmias. One hundred thirteen patients presented with sustained ventricular tachycardia that was hemodynamically stable, and 59 patients presented with cardiac arrest. Seventy-one patients without previously documented or suspected ventricular arrhythmias were also studied to determine the specificity of our electrophysiologic study protocol. The stimulation protocol included single, double, and triple right ventricular extrastimuli and rapid ventricular pacing at multiple cycle lengths performed at one or more right ventricular sites. Stimulation was performed at one or more left ventricular sites in patients with documented spontaneous arrhythmias when right ventricular programmed stimulation failed to induce sustained ventricular tachycardia. Ventricular tachyarrhythmias were induced in 110 (97%) of the patients who presented with sustained ventricular tachycardia, in 48 (81%) of the patients who presented with cardiac arrest, and in 28 (40%) of the patients without documented spontaneous arrhythmias. Right ventricular triple extrastimuli induced tachycardia in 22% of patients who presented with sustained ventricular tachycardia vs 46% of those who presented with cardiac arrest (p less than .001). Left ventricular stimulation was required for tachycardia induction in 3% of patients with stable tachycardia vs 19% of those with cardiac arrest (p less than .01). Triple extrastimuli induced 57% of tachycardias in the 28 patients without spontaneous arrhythmias, and virtually all of these tachycardias were polymorphic and nonsustained. The cycle lengths of tachycardias induced in each group by double and triple extrastimuli were similar, but the tachycardias induced in patients with cardiac arrest were significantly faster than those induced in the ventricular tachycardia group (mean cycle length 218 vs 291 msec, p less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)
Buxton et al. (1984) conducted an observational in Sustained ventricular tachyarrhythmias (n=243). Electrophysiologic study with single, double, and triple extrastimuli vs. Stable ventricular tachycardia vs cardiac arrest was evaluated on Tachycardia induction by right ventricular triple extrastimuli (p=<0.001). Right ventricular triple extrastimuli induced tachycardia in 46% of patients presenting with cardiac arrest compared to 22% of those with stable sustained ventricular tachycardia (p<0.001).