Electrocardiogram indicators of right ventricular dilation in repaired tetralogy of Fallot patients

Background: Patients with surgically repaired tetralogy of Fallot (rTOF) often develop chronic pulmonary regurgitation (PR), necessitating pulmonary valve replacement (PVR). While cardiac MRI is crucial for PVR timing, its availability is limited. This study evaluates electrocardiographic (ECG) findings–specifically the R-wave amplitude in lead V1 (V1R) and the sum of the R-wave amplitude in lead V1 and the deepest S-wave amplitude in lead V5 or V6 (V1R + V5S or V6S)–as predictors of cardiac MRI findings. Patients and methods: We retrospectively analyzed 35 rTOF patients (mean age 34 ± 9 years; 60% male) who underwent cardiac MRI from 2019 to 2022, assessing correlations between ECG parameters (V1R, V1R + V5S or V6S, and QRS duration) and MRI findings (RVESVI and RVEDVI). Results: V1R showed significant correlation with RVESVI (r = 0.486, p = 0.003) and was notably higher in patients with RVESVI ≥ 80 mL/m². A V1R cutoff of 20 mm identified RVESVI ≥ 80 mL/m² with 67% sensitivity and 77% specificity. Conclusions: V1R on ECG may help predict the need for cardiac MRI, aiding in the timely PVR planning for rTOF patients.