VT ablation reduces ICD therapy, hospitalization for arrhythmia

Ablation of ventricular tachycardia (VT) before placement of an implantable cardioverter-defibrillator (ICD) is associated with a reduced risk of appropriate ICD therapy or ventricular arrhythmia (VA)-related hospitalization in patients with ischaemic cardiomyopathy (ICM) and chronic total occlusion of an infarct-related artery (IRA-CTO), findings from the PREVENTIVE VT trial have shown.

After a mean follow-up of 44.7 months, only five (16.7 percent) of the 30 patients who had VT ablation prior to ICD implantation experienced the primary composite outcome of appropriate ICD therapy and unplanned hospital admission for symptomatic VAs. Whereas for those who received ICD only (standard therapy; n=30), the incidence of the primary endpoint was nearly threefold higher (n=13; 43.3 percent). Multivariate regression analysis generated a hazard ratio (HR) of 0.32 (p=0.032).

There was also a reduction in unplanned cardiac hospital admission for VAs/heart failure (HF; HR, 0.22; p=0.009) on multivariate analysis. [EHRA 2024, Late-Breaking Science: ablation]

Univariate analyses also favoured the ablation vs standard therapy arm, as reflected by the lower incidences of appropriate ICD therapy (16.7 percent vs 40 percent; HR, 0.37; p_log-rank=0.051), unplanned hospital admission for symptomatic VAs (0 percent vs 30 percent; p_log-rank=0.001), unplanned cardiac hospital admission for VAs/HF (13.3 percent vs 53.3 percent; HR, 0.21; p_log-rank=0.002), and electrical storm (0 percent vs 20 percent; p_log-rank=0.01) with the former vs the latter.

Albeit lacking statistical significance, the ablation arm had lower rates of cardiovascular death (13.3 percent vs 26.7 percent; HR, 0.41; p_log-rank=0.139), HF hospitalization (13.3 percent vs 33.3 percent; HR, 0.36; p_log-rank=0.074), and death from any cause (26.7 percent vs 40 percent; HR, 0.55; p_log-rank=0.194) than the standard therapy arm.

Only two major complications were reported in the catheter ablation arm. One was ischaemic stroke, which resolved without consequences. The other was a complete atrioventricular block, which required implantation of a cardiac resynchronization therapy defibrillator device.

Deferred ablation – worse outcomes?

Deferred ablation may worsen prognosis, reduce success rates, and lead to more periprocedural complications. [J Am Coll Cardiol 2017;69:2105-2115; Heart Rhythm 2015;12:1997-2007] Hence, the investigators sought to evaluate the efficacy and safety of substrate ablation before ICD implantation for reducing ICD interventions and VA-related hospitalizations.

“We hypothesized that ablation early in the course of the disease – when patients have a lower burden of comorbidities – might be associated with fewer periprocedural complications and improved clinical outcomes compared to withholding the procedure until several ICD shocks have occurred,” noted principal investigator Dr David Zizek from the University Medical Centre Ljubljana, Slovenia, in a press release.

Zizek and colleagues randomized 60 patients 1:1 to ablation prior to ICD placement or ICD only. In the ablation arm, all but one were male, age at enrolment was 65 years, and >40 percent had IRA-CTO in the right coronary artery (RCA). In the standard therapy arm, 26 patients were male, age at enrolment was 71 years, and two-thirds had IRA-CTO in the RCA.

The second most common IRA-CTO location was the left circumflex artery (36.7 percent [ablation arm] and 20 percent [standard therapy arm]), followed by the left anterior descending artery (26.7 percent and 20 percent, respectively). About a quarter of participants had CTOs in two vessels.

A potential treatment alternative

“Our study shows that a primary prevention ablation strategy can be a safe and effective treatment option to prevent ICD interventions and arrhythmia-related hospitalizations,” said Zizek.

“Our study also highlights the importance of identifying ICM patients with a high risk of VAs in whom substrate ablation might prevent arrhythmias and consequent debilitating ICD shocks, while outweighing the potential for procedural complications,” he added.

The investigators called for further trials that are sufficiently powered to ascertain the potential of catheter ablation as a primary prevention strategy in this setting.