A fragmented QRS complex (fQRS) was defined as additional spikes within the QRS complex in two contiguous leads of a standard 12-lead electrocardiogram (ECG). It has been shown to be an indicator of myocardial fibrosis. But, the correlation between the location of fQRS in the ECG and the myocardial scar is poorly documented.

The aim of this study was to investigate the correlation between the location of fQRS and late gadolinium enhancement in cardiac magnetic resonance in patients with heart failure with reduced ejection fraction (HFrEF).

This study had included 72 consecutive patients diagnosed with HFrEF, who underwent Cardiac magnetic resonance (CMR) with late gadolinium enhancement sequences(LGE). ECG was systematically realized at admission with detailed reading of the patterns of fragmented QRS.

The mean age was 57±10years (58, 81% men). Our patients were diagnosed with HFrEF (EF=27±8%) which was related to ischemic cardiomyopthy in 43% of cases. Most of patients (67%) were symptomatic of dyspnea NYHA functional class II. LGE and fQRS were present in 47(65%) and 50(69%) patients respectively. Regardless of the localization, the presence of fQRS in ECG showed a moderate correlation with LGE in CMR (kappa=0,52; P<10⁻⁴). As well, The correlation of each localization with those of LGE was moderate with significant p value: 41% had fQRS in anterior leads and LGE in anterior wall (kappa=0,23;P=0,03),76% had fQRS in inferior leads and LGE in inferior wall (kappa=0,4; P=0,001) and 67% had fQRS in lateral leads with LGE in lateral wall (kappa=0,35; P=0,002).

The fQRS is a simple, and readily available ECG parameter that can be correlated with fibrosis diagnosed in CMR.