Risk stratification of ventricular arrhythmias in repaired tetralogy of Fallot

Introduction and objectives: Risk stratification of ventricular arrhythmias in patients with repaired tetralogy of Fallot (rTOF) remains unresolved. We aimed to identify right ventricular (RV) electrophysiological parameters potentially associated with a higher risk of ventricular arrhythmias in patients with rTOF. Methods: We included all consecutive patients with rTOF who underwent RV electroanatomical mapping at a single tertiary center. We used logistic regression modeling to identify those variables associated with an increased risk of clinical or induced ventricular tachycardia (VT), or clinical VT exclusively. Results: Twenty-one of the 56 patients included had clinical or induced VT. A high- frequency of premature ventricular contractions/nonsustained VT (OR, 11.34; 95%CI, 1.50-85.97; P =.019), an HV interval > 55 ms (OR, 21.20; 95%CI, 3.12-144.14; P =.002), and RV activation time (ms) (OR [per 10 ms intervals], 1.34; 95%CI, 1.02-1.75; P =.035) proved to be associated with clinical or induced VT. The model including this information had good discrimination ability, with an area under the curve of 0.884 (95%CI, 0.79-0.97; P <.001). When considering only clinical VT as the outcome of interest, only an HV interval > 55 ms (OR, 9.65; 95%CI, 1.41-66.14; P =.021) and high-frequency of premature ventricular contractions/nonsustained VT (OR, 13.14; 95%CI, 1.95-88.54; P =.008) were independently associated (area under the curve of 0.836 [95%CI, 0.663- 1.000; P =.002]). Conclusions: High-frequency of premature ventricular contractions/nonsustained VT, an HV interval > 55 ms and RV activation time are factors associated with an increased risk of ventricular arrhythmias in patients with rTOF. (C) 2020 Sociedad Espanola de Cardiologia. Published by Elsevier Espana, S.L.U. All rights reserved.