APPRAISE ATP Trial: Antitachycardia Pacing Prolongs Time to First Shock in Primary Prevention ICD Patients

The APPRAISE ATP randomized clinical trial revealed that administering a single burst of ATP before delivering a shock in primary prevention ICD recipients using modern detection programming extended the time until the first all-cause ICD shock.

The introduction of new programming guidelines that minimize premature and inappropriate therapies, coupled with advancements in implantable cardioverter-defibrillator technologies that do not include traditional endocardial antitachycardia pacing capabilities, necessitates a reassessment of ATP as the primary approach for terminating fast ventricular tachycardias (VTs) in patients receiving primary prevention ICDs.

Against the above background, Claudio Schuger, Clinical Cardiac Research Center, University of Rochester, Rochester, New York, and colleagues aimed to evaluate the role of ATP in terminating fast VTs in primary prevention ICD recipients utilizing modern programming techniques.

For this purpose, a global, prospective, double-blind, randomized clinical trial was conducted with an equivalence design involving patients at 134 sites across eight countries from September 2016 to April 2021, with follow-up concluding on July 6, 2023. Participants were required to have a primary prevention ICD indication, including a left ventricular ejection fraction of 35% or less.

Patients were randomized in a 1:1 ratio to receive either ATP plus shock or shock only. The primary endpoint was the time to the first all-cause shock, while secondary endpoints included the time to the first appropriate and inappropriate shock, all-cause mortality, and the combined metric of time to first all-cause shock plus all-cause mortality.

Based on the study, the researchers reported the following findings:

• A total of 2,595 patients were randomized, with a mean age of 63.9 years and 22.4% being female.
• After a mean follow-up period of 38 months, the first all-cause shock occurred in 129 participants from the ATP plus shock group and 178 participants from the shock-only group.
• The hazard ratio (HR) for the primary endpoint was 0.72, indicating a significant superiority of the ATP plus shock group over the shock-only group.
• In an intention-to-treat analysis during follow-up, the total shock burden per 100 patient years was similar, at 12.3 for the ATP plus shock group and 14.9 for the shock-only group.

The authors concluded that antitachycardia pacing is effective as a first-line therapy for prolonging the time to the first all-cause shock, even though the overall shock burden did not differ significantly between the groups during follow-up.

Reference:

Schuger C, Joung B, Ando K, et al. Assessment of Antitachycardia Pacing in Primary Prevention Patients: The APPRAISE ATP Randomized Clinical Trial. JAMA. Published online October 03, 2024. doi:10.1001/jama.2024.16531