Procedural non-inducibility and post-ablation amiodarone therapy as complementary determinants of 1-year outcome after electrical storm ablation

Background Electrical storm (ES) is associated with substantial mortality despite contemporary catheter ablation strategies. Amiodarone is frequently continued after ablation, yet its relationship with long-term survival in ES remains poorly defined. Purpose We aimed to evaluate the relative impact of procedural non-inducibility and post-discharge amiodarone therapy on 1-year mortality and composite clinical outcomes. Methods We retrospectively analyzed 101 consecutive patients who underwent radiofrequency catheter ablation for drug-refractory ES (2014-2022). Acute complete success was defined as the non-inducibility of any sustained monomorphic ventricular tachycardia (VT) during aggressive programmed ventricular stimulation with 4 extra stimuli at the end of the procedure. Primary endpoints were 1-year all-cause mortality and a composite endpoint of death or VT recurrence. Multivariable logistic regression was used to adjust for age, procedural success, baseline left ventricular ejection fraction, severe heart failure (NYHA III/IV), and chronic kidney disease. Results Acute procedural success was achieved in 79.2% of patients (80/101). The overall 1-year mortality rate was 8.9% (9/101). Mortality was lower in patients with procedural success than in those with residual inducibility (6.3% vs 19.0%; p=0.067). Amiodarone was maintained at discharge in 71.3% of the cohort. In univariate analysis, amiodarone continuation was associated with higher composite event rates (p=0.015) but showed no significant association with 1-year mortality (9.7% vs. 6.9%, p=0.652) (Figure 1). In the multivariable model, acute complete success emerged as the only significant independent predictor of favourable 1-year composite outcomes (OR: 0.177, 95% CI 0.06-0.51; p < 0.001) (Figure 2). Conversely, amiodarone at discharge was not an independent predictor of outcomes (p=0.611) after adjusting for procedural success and baseline clinical frailty. Conclusion Long-term survival and clinical stability after electrical storm ablation are primarily driven by non-inducibility rather than post-ablation amiodarone therapy. Although amiodarone use is common and correlates with higher event rates in unadjusted analyses - likely reflecting a higher baseline risk profile - it provides no independent survival benefit. These findings suggest that achieving a successful electrical outcome is the most significant determinant of the 1-year prognosis.