Iwakami N, Aiba T, Kamakura S, et al. - Whether benign early repolarization patterns (ERPs) could be distinguished from malignant ones via high spatiotemporal resolution 64-channel magnetocardiography (MCG), was determined in this study. Of 2,636 individuals who received MCG in experts' facility, 116 (43 ± 18 years old, 54% male) exhibiting inferior and/or lateral ERP in ECG and with no structural heart disease were identified, including 13 survivors of ventricular fibrillation (VF) (ERP-VF(+)) and 103 with no history of VF (ERP-VF(−)). QRS duration (MCG-QRSD), root-mean-square of the last 40 ms (MCG-RMS40), and low amplitude (< 10% of maximal) signal duration (MCG-LAS) constituted the MCG parameters that were measured in a time-domain waveform of relative current magnitude. A significantly longer MCG-QRS and lower MCG-RMS40 were seen in ERP-VF(+) individuals vs ERP-VF(−), with no difference in MCG-LAS. A significantly larger area under the ROC curve was demonstrated by MCG-QRSD and MCG-RMS40 vs J-peak amplitude in ECG. For identifying VF(+) depending on MCG-QRSD ≥ 100 ms and MCG-RMS40 ≤ 0.24, the sensitivity, specificity, and odds ratio were estimated to be 69%, 74%, and 6.33, and 92%, 48%, and 10.9, respectively. Overall, magnetocardiography effectively distinguished malignant and benign ERPs.