Correlation of Fragmented QRS with Right Ventricular Indexes and Fibrosis in Patients with Repaired Tetralogy of Fallot, by Cardiac Magnetic Resonance Imaging

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.