Real-world performance of intrinsic antitachycardia pacing: Primary results from a global prospective postapproval registry study

BACKGROUND: Antitachycardia pacing (ATP) can prevent defibrillator shocks and associated adverse outcomes. Opportunities to enhance ATP performance exist, particularly for rapid monomorphic ventricular tachycardia (MVT). Intrinsic ATP (iATP) is the first closed-loop algorithm that designs and auto-adjusts ATP therapy in real time. OBJECTIVE: This study aimed to evaluate iATP performance in a large, real-world cohort. METHODS: This global, prospective, observational study enrolled patients with an iATP-enabled implantable cardioverter-defibrillator or cardiac resynchronization therapy-defibrillator device. The primary objective, to demonstrate iATP could effectively terminate >60% of MVT episodes in the fast ventricular tachycardia (VT) zone, was analyzed using the generalized estimating equations (GEE) method. Additional analyses included overall effectiveness and the rate of MVT acceleration resulting in shock. A post hoc analysis used GEE models to compare iATP data with standard ATP from a retrospective cohort. RESULTS: In total, 1875 enrolled patients were followed for a total of 3200 patient-years, yielding 2575 iATP-treated MVT episodes. Of 265 iATP-treated episodes in the fast VT zone (73 patients), the GEE-estimated success rate was 89.7% (95% confidence interval [CI] 83.6-93.7), exceeding the primary objective. The GEE-estimated rate of iATP-associated MVT acceleration resulting in shock was 2.3%. Compared with standard ATP, iATP almost doubled the odds of VT termination (adjusted odds ratio 1.87; 95% CI 1.32-2.66; P = .0005) and halved the odds of acceleration resulting in shock (adjusted odds ratio 0.43; 95% CI 0.25-0.74; P = .0026). CONCLUSION: In routine practice, iATP was highly effective and safe across all VT rates. Although exploratory, iATP had overall superior termination rates and a lower chance of acceleration resulting in shock than standard ATP.