Electrical storm ablation: absolute benefit, risk-score discordance, and clinical equity

The multicentre study by Ninni et al.¹ provides the strongest evidence to date that catheter ablation (CA) in electrical storms (ES) is not merely a salvage strategy, but a therapy with profound survival benefit across risk strata. Beyond the hazard ratios, the derived treatment metrics can be estimated and highlight the extraordinary absolute benefit. In high iVT patients, 1-year mortality fell from 52 to 20%,¹ an absolute reduction of 32% corresponding to a number needed to treat (NNT) of 3.1. Patients with high PAINESD showed almost identical benefit (54% to 26%; NNT, 3.6). Even in low-risk groups, NNT was 8–9, favourable compared to many established cardiovascular therapies. Importantly, survival curves diverged by 90 days in high iVT patients, whereas low-risk patients required nearly a year to demonstrate benefit. This time-dependent gradient positions ablation in patients with high-risk iVT as an emergency therapy, not an elective one.

Paradoxically, those who would gain the most were the least likely to undergo ablation. Only 35–39% of high-risk patients received the procedure compared with 43–47% in lower-risk groups, despite being disproportionately ischaemic (90%) and diabetic (over 50%).¹ This treatment gap suggests a misalignment between access and need, possibly reflecting physician preference for ‘healthier’ procedural candidates rather than those with the greatest absolute survival gain. Future practice must invert this logic, prioritizing patients with ischaemic and diabetic ES for early ablation.

The most important unaddressed limitation is the discordance between PAINESD and iVT scores. While nearly a quarter of the patients were high-risk for both, approximately 15% fell into discordant categories, and outcomes for this subgroup were not reported.¹ Clinicians often encounter conflicting classifications, yet this study does not provide guidance on which score should govern urgent triage. Procedural safety also warrants scrutiny. Stroke or transient ischaemic attack occurred in 2.7% of ablations,¹ more than twice the rate reported in elective VT ablation series.^2,3 This hazard, likely amplified by unstable haemodynamics and anticoagulation challenges, is outweighed by survival gains in high-risk patients, but could decrease benefit in lower-risk groups. Chronic kidney disease, overrepresented in high-risk patients, compounds this risk, yet it was not analysed as an effect modifier.⁴ Other concerns include the underrepresentation of women (14.6%) and the absence of procedural timing data, although previous work shows that emergency vs. delayed ablation critically affects outcomes.^1,5–8

In summary, CA in high iVT patients yields exceptionally low NNTs with survival benefits manifesting within weeks, supporting urgent referral and prioritization. Unresolved score discordance and incomplete safety analysis, however, leave uncertainty in triage. Addressing these gaps will be essential to ensure that the extraordinary efficacy of ablation in ES is translated into equitable and optimized care.