High-resolution magnetocardiography identified malignant early repolarization patterns, with MCG-RMS40 ≤ 0.24 strongly associated with a history of ventricular fibrillation (OR 10.9; 95% CI 1.37-86.8).
Observational (n=116)
No
Does high-resolution magnetocardiography improve the identification of malignant early repolarization patterns compared to standard ECG in patients with early repolarization pattern and no structural heart disease?
High-resolution magnetocardiography parameters (MCG-QRSD and MCG-RMS40) can effectively distinguish malignant from benign early repolarization patterns better than standard ECG J-peak amplitude.
Effect estimate: OR 10.9 (95% CI 1.37-86.8)
p-value: p=0.01
BACKGROUND: The early repolarization pattern (ERP) in electrocardiography (ECG) has been considered as a risk for ventricular fibrillation (VF), but effective methods for identification of malignant ERP are still required. We investigated whether high spatiotemporal resolution 64-channel magnetocardiography (MCG) would enable distinction between benign and malignant ERPs. METHODS: Among all 2,636 subjects who received MCG in our facility, we identified 116 subjects (43 ± 18 years old, 54% male) with inferior and/or lateral ERP in ECG and without structural heart disease, including 13 survivors of VF (ERP-VF(+)) and 103 with no history of VF (ERP-VF(-)). We measured the following MCG parameters in a time-domain waveform of relative current magnitude: (a) QRS duration (MCG-QRSD), (b) root-mean-square of the last 40 ms (MCG-RMS40), and (c) low amplitude (<10% of maximal) signal duration (MCG-LAS). RESULTS: Compared to ERP-VF(-), ERP-VF(+) subjects presented a significantly longer MCG-QRS (108 ± 24 vs. 91 ± 23 ms, p = .02) and lower MCG-RMS40 (0.10 ± 0.08 vs. 0.25 ± 0.20, p = .01) but no difference in MCG-LAS (38 ± 22 vs. 29 ± 23 ms, p = .17). MCG-QRSD and MCG-RMS40 showed significantly larger area under the ROC curve compared to J-peak amplitude in ECG (0.72 and 0.71 vs. 0.50; p = .04 and 0.03). The sensitivity, specificity, and odds ratio for identifying VF(+) based on MCG-QRSD ≥ 100 ms and MCG-RMS40 ≤ 0.24 were 69%, 74%, and 6.33 (95% CI, 1.80-22.3), and 92%, 48%, and 10.9 (95% CI, 1.37-86.8), respectively. CONCLUSION: Magnetocardiography is an effective tool to distinguish malignant and benign ERPs.
Iwakami et al. (2020) conducted an observational in Early repolarization pattern (ERP) (n=116). High-resolution 64-channel magnetocardiography (MCG) vs. ERP-VF(-) subjects was evaluated on Identification of VF(+) based on MCG-RMS40 ≤ 0.24 (OR 10.9, 95% CI 1.37-86.8, p=0.01). High-resolution magnetocardiography identified malignant early repolarization patterns, with MCG-RMS40 ≤ 0.24 strongly associated with a history of ventricular fibrillation (OR 10.9; 95% CI 1.37-86.8).