Diagnostic performance of the fragmented QRS complex on electrocardiogram for detecting myocardial scars assessed by 3.0 Tesla cardiac magnetic resonance imaging

Abstract Background Fragmented QRS complex (f-QRS) on a 12-lead electrocardiogram (EKG) with a 100 Hz low-pass filter is known to be related to ischemic myocardial scars. Cardiac magnetic resonance (CMR) imaging enhances tissue characterization capability resulting in a better myocardial scar assessment over other noninvasive imaging modalities. However, the diagnostic values of f-QRS on non-ischemic scars and f-QRS from EKG with a 40 Hz low-pass filter (routine filter in clinical practice) are unknown. Therefore, this study aims to evaluate the diagnostic performance of f-QRS (from EKG with 40 Hz and 100 Hz low-pass filters) for detecting any myocardial scars assessed by 3.0 Tesla CMR. Methods This cross-sectional study included patients who underwent a 3.0 Tesla CMR scan from May 2020 to May 2023. A 12-lead EKG with 0.15-40 and 0.15-100 Hz low-pass filters, performed on the same day of the CMR scan, was assessed for the presence of f-QRS. The ECG leads were divided into 3 categories (e.g., anteroseptal leads V1-V4; lateral leads I, aVL, V5-V6; and inferior leads II, III, aVF). The f-QRS was defined as the presence of R’ wave or notching in the nadir of the S wave in 2 contiguous leads. The primary outcome was the diagnostic performance of f-QRS from EKG in myocardial scar detection in the corresponding left ventricle (LV) segments. The secondary outcomes were to compare diagnostic performance between f-QRS from EKG with 0.15-40 and 0.15-100 Hz low-pass filters. Results The study involved 1,692 participants with a median age of 67 (IQR: 59-85) years old and 52.5% males. Myocardial scars were found in 826 (49%) participants. Male, history of CAD, and myocardial scars were significantly more frequent in the participants with f-QRS (59.4% vs 46%, 26.4% vs 20.6%, and 48.9% vs 37.3%, respectively). The sensitivity, specificity, positive predictive value, negative predictive value, and AUC of f-QRS from EKG with 0.15-100 Hz low-pass filter for detecting myocardial scars were 25.6%, 88.7%, 45.1%, 76.8%, and 0.57 for anteroseptal segments; 22.1%, 91.5%, 36.8%, 84.1%, and 0.57 for lateral segments; and 42.9%, 63.4%, 36.9, 68.9%, and 0.53 for inferior segments. The f-QRS from 0.15-100 Hz showed a higher sensitivity but lower specificity and PPV for all LV segments. NPV and AUC were not significantly different between the two filters. Conclusion This study demonstrates a high specificity and negative predictive value of f-QRS from a 12-lead EKG with 0.15-40 and 0.15-100 Hz low-pass filters in diagnosing myocardial scars when correlated to the corresponding LV segments.central illustrationbaseline charateristic