Relation between fragmented QRS complex to the right ventricular volumes and fraction of pulmonary regurgitation in patients with repaired tetralogy of Fallot

Patients with repaired tetralogy of Fallot (TOF) have not uncommonly fragmented QRS complexes (fQRS) on surface electrocardiogram. We suggested that the right heart hemodynamics might be correlated with both the number of leads showing fQRS (fQRS extent) and the QRS duration. A retrospective analysis of the magnetic resonance imaging (MRI) derived data of 30 patients following total correction of TOF was performed. The number of leads showing fragmentation (fQRS extent) as well as the QRS duration were assessed and tested for correlation with the right ventricular volumes and severity of pulmonary regurgitation (PR) as detected by MRI. Twenty-one patients had fQRS in at least 2 consecutive leads. fQRS correlated with larger right ventricular volumes and lower ejection fraction. fQRS in 5 leads was an accurate parameter in identifying an indexed right ventricular end diastolic volume >150 ml/m2 with a sensitivity of 87.5% and a specificity of 85.7%. Moreover, it was the most accurate parameter in detecting a PR fraction > 45%. To conclude, assessment of fQRS extent and duration is a simple, available, and an accurate parameter in identifying patients with significant right ventricular hemodynamic changes in repaired TOF patients.