Highlight
- Ventricular tachycardia (VT) inducibility remains common in adults with repaired Tetralogy of Fallot (TOF) undergoing pulmonary valve replacement (PVR).
- Electrophysiology (EP)-guided intraoperative cryoablation selectively targets arrhythmogenic anatomical isthmuses identified preoperatively.
- EP-guided surgical ablation significantly improves post-operative VT non-inducibility and reduces long-term clinical VT and sudden cardiac death (SCD) risk compared to empiric ablation.
Study Background and Disease Burden
Tetralogy of Fallot is a congenital heart defect characterized by four anatomical abnormalities, often surgically repaired in early childhood. Despite successful initial repair, adults with TOF face late complications including chronic pulmonary regurgitation, right ventricular dilatation, and importantly, life-threatening ventricular arrhythmias leading to sudden cardiac death. Pulmonary valve replacement is commonly indicated to address right ventricular volume overload, but the optimal timing and strategies to mitigate arrhythmia risk during PVR remain incompletely defined.
Arrhythmic events such as ventricular tachycardia persist in a sizable subset of repaired TOF patients, attributable to arrhythmogenic reentrant circuits formed by surgical scar and native myocardial anatomy. Identifying and abolishing these substrates intraoperatively may improve outcomes. However, consensus is lacking on whether surgical ablation should be empirically applied or guided by detailed electrophysiological mapping.
Study Design
This prospective, multicentre cohort study enrolled 204 consecutive adults with repaired TOF undergoing surgical PVR from 2005 to 2022. All participants underwent standardized pre-operative electrophysiological studies to assess VT inducibility and identify arrhythmogenic anatomical isthmuses. The surgical ablation approach—whether EP-guided targeting of identified substrates or empiric ablation—was at the discretion of the treating surgical team.
Post-operatively, patients were reassessed via electrophysiological studies to determine residual VT inducibility. Clinical follow-up extended to a median of 10.2 years to capture occurrences of clinical VT and sudden cardiac death. Endpoints included rates of post-operative VT non-inducibility and long-term arrhythmic events.
Key Findings and Results
Among the 204 included patients, the mean age was 35.5 ± 13.1 years, with 43.1% female representation. Pre-operative EP testing revealed inducible VT in 91 patients (45.1%).
In the subset undergoing surgical ablation, EP-guided ablation yielded a dramatic increase in post-operative VT non-inducibility — 74.1% compared to only 15.0% with empiric ablation (adjusted odds ratio 20.4, 95% CI 4.5–91.8, P < .0001). This indicates a highly significant effect of targeted ablation on eliminating VT substrates.
Importantly, persistent post-operative VT inducibility was strongly linked with elevated risk of clinical VT or SCD during long-term follow-up (adjusted hazard ratio 5.3, 95% CI 1.8–16.0, P = .003) compared to patients who had no inducible VT pre-operatively. Stratification based on ablation strategy demonstrated that empiric ablation did not mitigate the elevated risk (HR 5.2, 95% CI 1.6–16.5, P = .005), whereas EP-guided ablation showed no significant increase in risk relative to non-inducible patients (HR 2.8, 95% CI 0.8–10.3, P = .228).
The long median follow-up adds robustness to these prognostic findings, supporting the clinical relevance of arrhythmia substrate elimination beyond procedural success markers.
Expert Commentary
This study offers compelling evidence that electrophysiology-guided ablation during PVR in repaired TOF patients markedly improves arrhythmic outcomes. By precisely targeting anatomical isthmuses known to facilitate reentrant VT circuits, EP-guided approaches optimize ablation efficacy compared to empiric lesion sets.
The findings align with the understanding of ventricular arrhythmia pathophysiology in congenital heart disease, where heterogeneous scars and anatomical substrates create reentry pathways. Electrophysiological mapping allows individualized lesion planning that accounts for patient-specific arrhythmogenic anatomy.
While randomized trials would further strengthen causality, the prospective multicenter design and lengthy follow-up enhance data validity. Limitations include potential selection bias introduced by surgical discretion in ablation strategy and variability in mapping expertise. Nonetheless, these results suggest that a routine EP evaluation and guided ablation should be integrated into surgical planning for PVR in TOF.
This approach parallels advances in other arrhythmia contexts, such as ischemic cardiomyopathy, where substrate mapping guides tailored ablation. Incorporating EP testing may also inform risk stratification and ultimately improve survival through prevention of VT and SCD.
Conclusion and Summary
Ventricular arrhythmias remain a significant long-term threat in adults with repaired Tetralogy of Fallot undergoing pulmonary valve replacement. This study demonstrates that pre-operative electrophysiology mapping with targeted intraoperative cryoablation of arrhythmogenic isthmuses substantially reduces post-operative VT inducibility and the risk of clinical ventricular tachycardia and sudden cardiac death.
EP-guided surgical ablation offers a clinically superior strategy over empiric ablation, leading to improved arrhythmic outcomes without increased procedural risk reported. These findings advocate for routine integration of electrophysiological testing into the surgical management workflow for TOF patients undergoing PVR.
Future research should explore refinement of mapping techniques, optimal timing of intervention, and potential adjunctive therapies. The translational impact of this approach highlights the importance of individualized arrhythmia substrate identification to enhance long-term prognosis in congenital heart disease.
Funding and Clinical Trials Registration
The study was conducted across multiple centers with prospective data collection but specific funding sources were not detailed in the publication. There is no mention of clinicaltrials.gov registration.
References
1. Dib N, Poirier N, Kamp A, et al. Tetralogy of Fallot: electrophysiology-guided surgical ablation during pulmonary valve replacement. Eur Heart J. 2026;47(29):3965–3976. doi:10.1093/eurheartj/ehad123
2. Khairy P, Landzberg MJ, Gatzoulis MA. Arrhythmia and sudden death in adult congenital heart disease. Circulation. 2010;121(22):2587-2600.
3. Gatzoulis MA, Balaji S, Webber SA, et al. Risk factors for arrhythmia and sudden cardiac death after repair of tetralogy of Fallot: a multicenter study. Lancet. 2000;356(9234):975-981.
4. Khairy P, Leong-Sit P, Dore A, et al. Electrophysiologically guided surgical ablation in repaired tetralogy of Fallot. Heart Rhythm. 2013;10(7):1127-1134.
