What Is the Importance of Electrocardiography in the Routine Screening of Patients with Repaired Tetralogy of Fallot?

Background: In patients following complete repair of the tetralogy of Fallot, the duration of the QRS complex is associated with the size and mechanical function of the right ventricle, which are contemporarily assessed by cardiac magnetic resonance (CMR). Methods: 38 patients aged 18.0–54.9 years (median age 24.9 years) who had undergone complete repair of the tetralogy of Fallot were examined using CMR and concomitant 24 h ambulatory electrocardiography monitoring. We used statistical analysis to investigate the correlations between electrocardiographic parameters (heart rate, HR; PQ interval, PQ; QRS duration, QRS; and corrected QT interval, QTc) and CMR results (right ventricular ejection fraction, RVEF; right ventricular end-diastolic volume index, RVEDVI; and right ventricular end-systolic volume index, RVESVI) for patients after early and late repair. Results: The ECG-based parameters were not correlated with time since repair. There were significant correlations between QRS duration and RVEF (r = −0.61), RVEDVI (r = 0.56), and RVESVI (r = 0.54) for early operated patients but not for late-operated patients. No other substantial correlations were reported. Conclusion: Despite its role in screening for arrhythmias, electrocardiography has a limited role as a predictor of morphology and function of the right ventricle in patients after repair of the tetralogy of Fallot.