Slowly conducting anatomic isthmuses of tetralogy of Fallot: An opportunity for "prophylactic" ventricular tachycardia ablation.

Publication Title

Heart Rhythm

Document Type

Article

Publication Date

11-17-2024

Keywords

Ablation; Arrhythmia prevention; Sudden death; Tetralogy of Fallot; Ventricular tachycardia.; montana; missoula; sph

Abstract

BACKGROUND: Patients with repaired tetralogy of Fallot are at risk of ventricular tachycardia (VT) and sudden cardiac death. Most VTs arise from 5 slowly conducting anatomic isthmuses (SCAIs; conduction velocity ≤0.5 m/s) bound by the right ventriculotomy, ventricular septal defect patch, and tricuspid and pulmonic valves. Historically, risk stratification electrophysiologic studies involved programmed ventricular stimulation with VT induction guiding implantable cardioverter-defibrillator (ICD) implantation or VT ablation.

OBJECTIVE: This study aimed to evaluate a "prophylactic" strategy of ablating SCAIs even in the absence of inducible VT to reduce ICD implantation and arrhythmic events and to compare this with the "historical" strategy.

METHODS: This was a single-center, retrospective cohort study. The historical cohort underwent programmed ventricular stimulation to guide ICD implantation or VT ablation. The prophylactic cohort underwent right ventricular electroanatomic mapping and ablation of SCAIs. A composite end point of arrhythmic death, cardiac arrest, sustained VT, and ICD complication was compared between the cohorts.

RESULTS: Ninety-two patients with repaired tetralogy of Fallot had risk stratification electrophysiologic studies. Of 57 prophylactic patients, SCAIs were identified or ablated in 33 (58%), 16 (28%) had inducible VT before ablation, and 1 received ICD. Of 35 historical patients, 15 (43%) had inducible VT; 3 had cryoablation during pulmonic valve replacement and 11 received ICDs. No prophylactic patients met the composite end point during a median 21 months (interquartile range, 8-35 months) vs 10 (29%) historical patients during a median 125 months (interquartile range, 90-142 months; P = .017). There were no ablation-related complications.

CONCLUSION: Prophylactic SCAI ablation is associated with fewer ICD implantations and a reduction in incident arrhythmic events without ablation-related complications.

Area of Special Interest

Cardiovascular (Heart)

Specialty/Research Institute

Cardiology

DOI

10.1016/j.hrthm.2024.10.073

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