Johnson Bryce V, Sonderman Mark, Magoon Matthew J, Pistner Andrew, Hanna Bishoy, Bevan Graham H, McDonagh Rosemary, Boyle Patrick M, Robinson Melissa R, Akoum Nazem, Chatterjee Neal A, Krieger Eric V, Nazer Babak
Division of Cardiology, University of Washington Medical Center, Seattle, Washington.
Department of Bioengineering, University of Washington Medical Center, Seattle, Washington.
Heart Rhythm. 2025 Oct;22(10):2669-2677. doi: 10.1016/j.hrthm.2024.10.073. Epub 2024 Nov 17.
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.
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.
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.
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.
Prophylactic SCAI ablation is associated with fewer ICD implantations and a reduction in incident arrhythmic events without ablation-related complications.
