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 10ms 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 > 55ms (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> 55ms and RV activation time are factors associated with an increased risk of ventricular arrhythmias in patients with rTOF.
(Copyright © 2020 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.)