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

• Published in: Annals of noninvasive electrocardiology Vol. 25; no. 4; pp. e12741 - n/a
• Main Authors: Iwakami, Naotsugu, Aiba, Takeshi, Kamakura, Shiro, Takaki, Hiroshi, Furukawa, Toshiaki A., Sato, Tosiya, Sun, Wenxu, Shishido, Toshiaki, Nishimura, Kunihiro, Yamada‐Inoue, Yuko, Nagase, Satoshi, Shimizu, Wataru, Yasuda, Satoshi, Sugimachi, Masaru, Kusano, Kengo
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01.07.2020; John Wiley and Sons Inc
• Subjects: Amplitudes; Cardiovascular diseases; Coronary artery disease; early repolarization pattern; Echocardiography; EKG; Electrocardiography; Event-related potentials; Fibrillation; Heart diseases; Identification methods; Magnetocardiography; New Technologies; sudden cardiac death; Ventricle; Ventricular fibrillation; Waveforms; ventricular fibrillation; sudden cardiac death; early repolarization pattern; magnetocardiography; electrocardiography
• ISSN: 1082-720X; 1542-474X
• DOI: 10.1111/anec.12741

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.