Ventricular tachycardia substrates in young patients with repaired tetralogy of fallot

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main source(s): We acknowledge the support from Netherlands Cardiovascular Research lnitiative: An initiative with Dutch Heart Foundation and Hartekind. Background Patients repaired tetralogy Fallot (rTOF) have a time-dependent increase in risk ventricular tachycardia (VT) after age 30 years (Y), slow conducting anatomical isthmus (SCAI) 3, located between pulmonary annulus septal defect (VSD) patch, as dominant VT substrate (1-4). However, SCAI may be already present before 30Y. Purpose To assess (1) prevalence SCAI, (2) associated factors development, (3) occurrence clinical VT, rTOF patients <30Y. Methods From database 146 or related lesions who underwent electroanatomical mapping (EAM) programmed electrical stimulation (PES) 2007 2022 for treatment arrhythmias (VA), stratification valve replacement (PVR), those aged <30Y at time procedure were selected analysed. Results Of patients, 55 (38%) (median 16Y [IQR 14-22]); 33/55 (60%) had TOF, 9/55 (16%) TOF double outlet right ventricle (DORV), 13/55 (24%) complex variants, including 8 atresia VSD, 2 absent valve, 3 other variations. Initial intracardiac surgical repair 0.8Y 0.4-1.4]) was performed via ventriculotomy 10/55 (18%) palliative shunts 16/55 (29%). RV to artery (RV-PA) conduit inserted during initial early (<1Y) 12/55 (22%). In 14/55 (25%) (PVR) later life 10.1Y 2.7-14.3]). Five (9%) EAM/PES spontaneous VA, 40/55 (73%) PVR, stratification. Monomorphic inducible 8/55 (15%), 4/5 proven 7/8 (88%). (29%) could identified; no (1,2,4) present. note, 9/16 (56%) RV-PA repair/early comparison only 3/39 (8%) without SCAI. univariable analysis (OR 6.8 [95% CI 1.8-26.4]), 5.3 1.2-22.3]), any prior PVR 4.8 1.4-16.7]), conduit/early 15.4 3.3-71.8]) significantly 3. multivariable remained independent predictor 13.0 1.2-142.4]). Conclusions A is 29% referred VTs. placement (<1Y repair) young rTOF. Whether conduit/valve causes scarring infundibulum consecutive conduction and/or whether variants contribute requires additional studies.