Catheter ablation of well tolerated ventricular tachycardia in patients with structural heart disease: long term follow-up of 62 cases without automatic defibrillator implantation
Authors: Cardelli LS , Barbato G , Carinci V , Pergolini F , Leci E , Verardi R , Casella G 
Published: May 2022

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
The occurrence of a sustained monomorphic ventricular tachycardias (SMVT) in patients with underlying structural heart disease (SHD) is considered correlated to a poor prognosis, based on historical data in patients with heterogeneous heart disease and clinical presentation; therefore the recommendation for implantation of automatic implantable cardioverter defibrillator (AICD) is strong. Information about prognosis of patients with SMVT is still limited, but recent studies have established that these patients represent a low-risk subgroup for sudden death that could benefit from radiofrequency (RF) ablation of the arrhythmic substrate and the AICD implantation could be deferred during the follow up.

Purpose
Patients with well-tolerated SMVT, SHD and left ventricular ejection fraction (LVEF) over 30% can benefit from a primary VT ablation strategy without the immediate need for AICD implantation.

Methods
We reviewed consecutive SHD patients with LVEF over 30% admitted for the occurrence of SMVT and who were treated by RF ablation as a first-choice therapy in a single Italian center, between 2009 and 2020 and who were discharged without AICD implantation. The primary outcome of the study was a composite of all-cause death and recurrence of VT. The secondary outcome was death from all causes. Patients with similar characteristics but who underwent AICD implantation during the same period served as control group.

Results
Clinical and electrophysiological features of 62 patients were analyzed (Table 1). In the study group, 88% were male; the median age was 72 years (IQR 55-81) and the median LVEF was 50.0% (IQR 40.0-55.0). The estimated success rate of ablative procedures (defined as VT no longer inducible) was around 82%. After a median follow-up of 38.8 months (IQR 15.6-76.1), the primary outcome occurred in 24 patients and the secondary outcome in 11 patients. All-cause mortality was 17%, corresponding to an annual mortality rate of 4.3%. Ten patients died for non-cardiovascular causes and one for advanced heart failure. No patient in the study died from sudden death. During the follow-up, 10 patients (16.1%) underwent AICD implantation due to VT relapse. At 36 months, between study and control groups, there was no difference in either the primary composite outcome (HR 1.03, 95% CI 0.45-2.21, p = 0.98) or in the secondary outcome (HR 1.4, 95% CI 0.48-4.54, p = 0.49).

Conclusions
Patients with well-tolerated SMVT, SHD and LVEF over 30% represent a subgroup of patients at lower risk that can benefit of RF ablation as a first-choice therapy. Delay in AICD implantation, after a possible VT relapse or clinical worsening, appears to represent a safe therapeutic strategy. Therefore, it is ethical and desirable to start a prospective randomized clinical trial to evaluate the benefit and cost-effectiveness of this strategy, as an alternative to AICD implantation.