The benefit of a second burst antitachycardia sequence for fast ventricular tachycardia in patients with implantable cardioverter defibrillators

Background: In patients with implantable cardioverter defibrillators (ICDs), an empirical burst of antitachycardia pacing (ATP) is moderately effective in terminating fast ventricular tachycardias (FVTs). It is unknown whether, in the case of failure of a first burst, a second burst attempt increases the efficacy of the intervention, without increasing morbidity. Our aim was to evaluate the safety and efficacy of a strategy of programming successive ATP sequences for FVT episodes.

Methods: A prospective study evaluated the safety and effectiveness of programming successive ATP sequences for termination of FVT episodes (cycle lengths [CLs] 250-320 ms) treated by one ATP sequence and, in the event of failure, by successive ATP attempts or shocks.

Results: Over a median follow-up of 54 months, 267 FVT episodes (mean CL of 295 ± 18 ms) were detected in 35 patients. Effectiveness of the first burst ATP was 64% (65% GEE-adjusted, where GEE is generalized estimating equation) and increased significantly to 83% (75% GEE-adjusted) with the second burst ATP sequence (P = 0.01). In the remaining 17% of FVT episodes with failure of the second ATP, successive bursts and shocks were required. Multivariate analysis showed that primary prevention ICD (odds ratio [OR] 5.3, 95% confidence interval [CI] 1.9-14.5, P = 0.001), sinus rhythm (OR 4.34, 95% CI 1.4-13.4, P = 0.01), nonischemic cardiomyopathy (OR 2.36, 95% CI 1.2-4.8, P = 0.02), and longer VT CL (OR 1.32, 95% CI 1.1-1.6, P = 0.002) were independently associated with effectiveness of the first or second burst pacing sequence.

Conclusion: The addition of a second burst pacing attempt increases the effectiveness of ATP for FVT and, therefore, reduces the need for high-energy shocks.