Treatment of VT: iATP shows promising results in the fast ventricular tachycardia zone

Intrinsic anti-tachycardia pacing (iATP) showed an adjusted success rate of 89.7% in the fast ventricular tachycardia (FVT) zone, together with rates of 92.1% in the ventricular tachycardia (VT) and 72.8% in the ventricular fibrillation (VF) zones. Furthermore, low rates of monomorphic VT acceleration with shock and arrhythmia-related syncopes were found.

“We all know that standard ATP can painlessly terminate VT and avoid ICD-shock,” Dr Pierre Ollitrault (University Hospital of Caen, France) stated [1]. However, the efficacy of standard ATP is limited to 52%-75% in rapid VT over 188 bpm. Dr Ollitrault informed that the automated loop iATP algorithm provides tailored ATP, relying on the very basic principles of VT entrainment and response to entrainment.

Between 2020 and 2024, the post-approval, prospective, international observational registry study enrolled 1875 patients with single chamber or dual chamber cardiac resynchronisation therapy (CRT)-devices that were enabled for iATP in one of the possible programming zones. Follow-up was performed by remote monitoring and every episode was assessed by the independent review committee of the study. The primary endpoint of the study set to demonstrate a >60% efficacy in the FVT zone.

During a median follow-up of 15.8 months, corresponding to 2684 follow-up years, over 3300 spontaneous episodes were adjudicated as VT receiving ATP or shock, about 90% due to monomorphic VT. Out of 265 primary endpoint events in the FVT zone, 91.3% were successfully treated with iATP, leading to an iATP success rate of 89.7% after adjustment for multiple episodes in 1 patient. Adjusted iATP success rates for the VT and the VF zone were 92.1% and 72.8%, respectively.

Safety findings observed adjusted rates of 4.4% for monomorphic VT episodes with acceleration and 2.3% with acceleration ensuing shock. Also, 23 of arrhythmia-related syncopes were adjudicated, with about 11 of them associated to iATP.

“Even though we report one of the highest success rates of ATP from a modern defibrillator cohort, we might have been missing some electrogram data which had been erased from the ICD, but also some minor clinical data,” Dr Ollitrault conceded when discussing possible study limitations. In conclusion, he underlined the safety of iATP and the overall high efficacy of iATP over all programmable zones in one of the largest ATP studies.

1. Ollitrault P, et al. Intrinsic antitachycardia pacing (iATP) algorithm success in the fast ventricular tachycardia zone: primary results from the post approval study. Late-breaking science 1, EHRA 2025, 30 March-01 April, Vienna, Austria.

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Posted on 6 May 20256 May 2025