Background It is well-established that fragmented QRS complexes (fQRS) on the 12-lead ECG are a predictor of delayed gadolinium enhancement (DGE) on Cardiac MRI (CMR) and indicate myocardial scar or fibrosis in patients with coronary artery disease and dilated cardiomyopathy. Moreover, fQRS appear to correlate well with arrhythmic events and mortality in these cohorts. However the significance of fQRS in hypertrophic cardiomyopathy (HCM) is yet to be established. We sought to determine whether the presence of fQRS is a predictor of delayed gadolinium enhancement (DGE) on CMR in patients with HCM.
Methods The 12-lead ECGs of 82 consecutive patients with HCM who underwent CMR with gadolinium were analysed for the presence of fQRS by two independent readers blinded to the CMR findings. Patients with documented myocardial infarction (n=3) were excluded from further analysis. The ECGs were correlated to CMR findings, and patients separated into DGE positive (DGE+ve; n=44) and negative (DGE−ve; n=35) groups. ECG territories of fQRS were correlated with myocardial segments of DGE on CMR, in order to determine whether areas of fQRS predicted areas of DGE.
Results Patients from the DGE+ve and DGE-ve groups were of similar gender (75% vs 77% male respectively, p=1.00) and age (54 Â± 19 vs 57 Â± 11 years respectively, p=0.41). Fragmented QRS complexes were significantly more prevalent in the DGE+ve group than in the DGE-ve group (68.2% vs 14.3%, p<0.001). The positive predictive value (PPV) of fQRS for DGE on CMR was 85.7%, with a specificity of 85.7%, sensitivity of 68.2% and negative predictive value of 68.2%. In the DGE+ve group with fQRS (n=30), fQRS ECG lead territory was predictive of regions of DGE on CMRI in 73.3% (n=22) of patients.
Conclusions The presence of fQRS on 12-lead ECG correlates with DGE on CMR in patients with HCM, with good specificity and PPV. Electrocardiographic territories containing fragmentation also correlate with myocardial segments of DGE on CMR. This simple, inexpensive method may therefore be valuable for predicting scar or fibrosis in patients with HCM. Future work should focus on correlating fQRS with risk factors and events to determine its use in risk stratification.
- Hypertrophic cardiomyopathy
- cardiac MRI
- delayed enhancement