Additional antitachycardia pacing programming strategies further reduce unnecessary implantable cardioverter-defibrillator shocks

Abstract

BACKGROUND Antitachycardia pacing (ATP) is routinely used to terminate ventricular tachyarrhythmias (VTs). However, little guidance exists on the most effective programming of ATP. OBJECTIVE This study evaluated whether additional ATP sequences are more effective in reducing implantable cardioverter-defibrillator shocks. METHODS In patients from the Shock-Less study, the number of overall shocks were compared between patients programmed to <= 3 ATP sequences (VT zone) and <= 1 ATP sequence (fast ventricular tachycardia [FVT] zone) (nominal group) and patients programmed to receive additional ATP sequences in VT (>3) or FVT (>1) zones. RESULTS Of the 4112 patients (15% receiving secondary prevention; 77% men; mean age 65.9 +/- 12.6 years), 1532 patients (37%) were programmed with additional ATP sequences (1025 with >3 ATP sequences in the VT zone; 699 patients with >1 ATP sequence in the FVT zone). Over a mean follow-up period of 19.6 +/- 10.7 months, 4359 VT/FVT episodes occurred in 591 patients. Compared with the nominal group, in patients with additional ATP programming, there was a 39% reduction in the number of shocked VT episodes (0.46 episodes per patient-year vs 0.28 episodes per patient-year; incidence rate ratio [IRR] 0.61; P < .001) and a 44% reduction in the number of shocked FVT episodes (0.83 episodes per patient-year vs 0.47 episodes per patient-year; IRR 0.56; P < .001). The reduction in shocked VT episodes was observed in both primary (IRR 0.68; 95% confidence interval 0.51-0.90; P = .007) and secondary (IRR 0.51; 95% confidence interval 0.35-0.72; P < .001) prevention patients. CONCLUSION Programming more than the nominal number of ATP sequences in both the VT and FVT zones is associated with a lower occurrence of implantable cardioverter-defibrillator shocks in clinical practice.