title: Utility of High-Resolution Magnetocardiography to Predict Later Cardiac Events in Nonischemic Cardiomyopathy Patients With Normal QRS Duration.
abstract: Nonischemic dilated cardiomyopathy (NIDCM) patients, even those with a narrow QRS, are at increased risk for major adverse cardiac events (MACE). We hypothesized that 64-channel magnetocardiography (MCG) would be useful to detect prognostic left intraventricular disorganized conduction (LiDC) by overcoming the limitations of fragmented QRS (fQRS, qualitative definitions, low specificity) and late potential (abnormality undetectable in earlier QRS).
  
  
  
  We evaluated LiDC on MCG, defined as significant deviation from a global clockwise left ventricular (LV) activation pattern, and conventional noninvasive predictors of MACE, including fQRS and late potential, in 51 NIDCM patients with narrow QRS (LV ejection fraction, 22±7%; QRS duration, 99±11 ms). MACE was defined as cardiac death, lethal ventricular arrhythmias, or LV assist device (LVAD) implantation. LiDC was present in 22 patients. Baseline characteristics were comparable between patients with and without LiDC, except for the ratio of positive late potential. During a mean follow-up of 2.9 years, MACE developed in 16 NIDCM patients (3 cardiac deaths, 9 lethal ventricular arrhythmias, and 4 LVAD). MACE was more incident in patients with LiDC (13/22) than in those without (3/29, P<0.001). Multivariate analysis revealed LiDC, but not fQRS or late potential, as the strongest independent predictor of MACE (hazard ratio 4.28, 95% confidence interval 1.30-19.39, P=0.015).
  
  
  
  MCG accurately depicts LiDC, a promising noninvasive predictor of MACE in patients with NIDCM and normal QRS.
authors.affiliation: Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kawakami
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takaki
authors.forename: Shuji
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kimura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakashima
authors.forename: Takeshi
authors.initials: T
authors.lastname: Aiba
authors.forename: Kengo F
authors.initials: KF
authors.lastname: Kusano
authors.forename: Shiro
authors.initials: S
authors.lastname: Kamakura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yasuda
authors.forename: Masaru
authors.initials: M
authors.lastname: Sugimachi
mesh_terms: D000328:Adult; D009202:Cardiomyopathies / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006353:Heart-Assist Devices; D006801:Humans; D053798:Magnetocardiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology / Q000503:physiopathology*