Identification of malignant early repolarization pattern by late QRS activity in high-resolution magnetocardiography

Naotsugu Iwakami, Takeshi Aiba, Shiro Kamakura, Hiroshi Takaki, Toshiaki A. Furukawa, Tosiya Sato, Wenxu Sun, Toshiaki Shishido, Kunihiro Nishimura, Yuko Yamada-Inoue, Satoshi Nagase, Wataru Shimizu, Satoshi Yasuda, Masaru Sugimachi, Kengo Kusano

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


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.

Original languageEnglish
Article numbere12741
JournalAnnals of Noninvasive Electrocardiology
Issue number4
Publication statusPublished - 2020 Jul 1
Externally publishedYes


  • early repolarization pattern
  • electrocardiography
  • magnetocardiography
  • sudden cardiac death
  • ventricular fibrillation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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