Correlation of fragmented QRS with right ventricular indexes and fibrosis in patients with repaired tetralogy of fallot, by cardiac magnetic resonance imaging

Abstract

Background: Repair of tetralogy of fallot (TOF) is associated with diffuse myocardial fibrosis. Cardiac magnetic resonance imaging (CMR) can visualize the areas with myocardial fibrosis. Presence of fragmented QRS (fQRS) implies the presence of the underlying myocardial scar. Despite the strong association between fQRS and myocardial pathologies, the impact of fQRS with myocardial fibrosis in post-TOF correction is unknown. Objectives: Here, we evaluated the possible predictive role of fQRS in repaired TOF cases and its relationship with cardiac function. Patients and Methods: Thirty two patients with previous history of repaired TOF were enrolled. The extent of fQRS was evaluated according to the number of leads with fQRS. After electrocardiographic evaluation, the participants underwent CMR. Results: Results showed a significant relationship between the right ventricular (RV) systolic diameter and fQRS (P = 0.014). Also, an inverse linear relationship was found between the number of fQRS edges and RVEF (r = 0.77, P = 0.0001). The mean QRS duration in those with positive and negative fQRS was 132 mm and 115.8 mm (P = 0.0001). Furthermore, a linear correlation was observed between the number of edges and the percentage of scar tissue (r = 0.88, P = 0.001). However, no relevance between gender and fQRS was detected (P = 0.26), and the relationship between RV diastolic diameter and fQRS was not significant (P = 0.1). Thus, fQRS could be used as a marker of RV systolic dysfunction in patients with tetralogy of fallot. Conclusions: We suggested the fQRS as a surrogate indicator of RV dysfunction in repaired TOF patients and showed that diagnostic and prognostic information of the patients were available by fQRS.