Heterogeneity of outcomes reporting in catheter ablation trials for ventricular tachycardia: a systematic review

We sought to systematically catalogue and compare outcomes definitions across prospective clinical trials and registries evaluating ablation in VT to assess the impact of heterogeneous definitions on reported outcomes.

A systematic review (PROSPERO: CRD 42024595265) was performed in accordance with PRISMA guidelines. We searched for prospective studies from January 2000 to November 2024. Randomized trials, single-arm feasibility studies, and prospective registries involving ≥10 patients undergoing VT ablation were included. Study outcomes and their definitions were extracted and categorized. Pooled analyses were performed for comparable randomized trial subgroups, and meta-regression evaluated the effect of VT outcome definitions on reported success and complications. Fifty-nine studies were included: 15 randomized trials, 6 feasibility studies, and 38 prospective studies/registries. Definitions of acute procedural success varied, with most using acute clinical VT non-inducibility and others using only elimination of the clinical VT. VT recurrence was the most frequently reported long-term outcome; however, definitions differed markedly (VT recurrence or recurrence causing device therapy). Pooled analysis of prophylactic ablation vs. delayed ablation showed reduced VT recurrence (HR 0.63, 95% CI: 46–0.86) but no difference in hospitalization or mortality. Meta-regression demonstrated that an outcome of any VT recurrence yielded a higher failure rate of 51.0% compared to stricter definitions, such as VT-causing therapy at 37.3% or VT-causing shock only at 23.4% (P = 0.002). Safety outcomes were inconsistently reported.

Outcome definition in VT ablation trials showed substantial heterogeneity, limiting cross-trial comparability and meta-analytic synthesis. Development of a minimum set of standardized outcomes for VT ablation may improve consistency and clinical interpretability of VT trials.