Assessment of Antitachycardia Pacing in Primary Prevention Patients: The APPRAISE ATP Randomized Clinical Trial.

Key Points: Question: Is antitachycardia pacing followed by shock clinically equivalent to a shock-only strategy in primary prevention implantable cardioverter-defibrillator recipients when programmed with long detection to therapy delays? Findings: In this randomized clinical trial that included 2626 patients and was designed as an equivalence trial with sequential superiority analysis of each group, anti-tachycardia pacing prior to shock reduced the relative risk of time to first all-cause shock by 28%, a significant difference. Meaning: Antitachycardia pacing is effective as a first-line therapy in prolonging time to first all-cause shock, although the shock burden was not significantly different between the groups during follow-up. Importance: The emergence of novel programming guidelines that reduce premature and inappropriate therapies along with the availability of new implantable cardioverter-defibrillator (ICD) technologies lacking traditional endocardial antitachycardia pacing (ATP) capabilities requires the reevaluation of ATP as a first strategy in terminating fast ventricular tachycardias (VTs) in primary prevention ICD recipients. Objective: To assess the role of ATP in terminating fast VTs in primary prevention ICD recipients with contemporary programming. Design, Setting, and Participants: This global, prospective, double-blind, randomized clinical trial had an equivalence design with a relative margin of 35%. Superiority tests were performed at interim analyses and the final analysis if equivalence was not proven. Patients were enrolled between September 2016 and April 2021 at 134 sites in 8 countries, with the last date of follow-up on July 6, 2023. Patients were required to have an indication for a primary prevention ICD, including left ventricular ejection fraction less than or equal to 35%. Interventions: Patients were randomized in a 1:1 ratio to receive ATP plus shock vs shock only. Main Outcomes and Measures: The primary end point was time to first all-cause shock. Secondary end points included time to first appropriate shock, time to first inappropriate shock, all-cause mortality, and the composite of time to first all-cause shock plus all-cause mortality. Results: A total of 2595 patients were randomized (mean age, 63.9 years; 22.4% were females). At a mean follow-up of 38 months, first all-cause shock occurred in 129 participants in the ATP plus shock group and 178 participants in the shock only group. The hazard ratio (HR) for the primary end point was 0.72 (95.9% CI, 0.57-0.92), with P =.005 for superiority of the ATP plus shock group over the shock only group. During follow-up in an intention-to-treat analysis, the total shock burden per 100 patient-years was not statistically different, at 12.3 and 14.9, respectively (P =.70). Conclusions and Relevance: The use of a single burst of ATP prior to shock in primary prevention ICD recipients with modern ICD detection programming prolonged the time to first all-cause ICD shock. Trial Registration: ClinicalTrials.gov Identifier: NCT02923726 This randomized clinical trial assesses the role of antitachycardia pacing in terminating fast ventricular tachycardia in primary prevention patients with implantable cardioverter-defibrillators with contemporary programming. [ABSTRACT FROM AUTHOR]