Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project
Authors: Schiavone Marco , Gasperetti Alessio , Compagnucci Paolo , Vogler Julia , Laredo Mikael , Montemerlo Elisabetta , Gulletta Simone , Breitenstein Alexander , Ziacchi Matteo , Martinek Martin , Casella Michela , Palmisano Pietro , Kaiser Lukas , Lavalle Carlo , Calò Leonardo , Seidl Sebastian , Saguner Ardan M , Rovaris Giovanni , Kuschyk Jürgen , Biffi Mauro , Di Biase Luigi , Dello Russo Antonio , Tondo Claudio , Della Bella Paolo , Tilz Roland , Forleo Giovanni B ,   iSUSI investigators, Schiavone M , Gasperetti A , Arosio R , Viecca M , Forleo G B , Ziacchi M , Diemberger I , Angeletti A , Biffi M , Fierro N , Gulletta S , Della Bella P , Tondo C , Mitacchione G , Curnis A , Compagnucci P , Casella M , Dello Russo A , Santini L , Pignalberi C , Magnocavallo M , Piro A , Lavalle C , Picarelli F , Ricciardi D , Bressi E , Calò L , Montemerlo E , Rovaris G , De Bonis S , Bisignani A , Bisignani G , Russo G , Pisanò E , Palmisano P , Guarracini F , Vitali F , Bertini M , Vogler J , Fink T , Tilz R , Fastenrath F , Kuschyk J , Kaiser L , Hakmi S , Laredo M , Waintraub X , Gandjbakhch E , Badenco N , Breitenstein A , Saguner A M , Martine M , Seidl S , Di Biase L 
Published: April 2024

Abstract

Aims
Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers.

Methods and results
International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA− cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA−; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA−; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100–0.681), P = 0.006].

Conclusion
In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up.

ClinicalTrials.gov identifier
NCT0473876.