Abstract 17191: Fragmentation Assessed by Magnetocardiography but not Electrocardiogram Can Predict Future Cardiac Events in Patients with Non-ischemic Dilated Cardiomyopathy and Narrow QRS
Background: Fragmented QRS (fQRS) in 12-lead ECG, ascribed to myocardial scar, has been shown to predict future cardiac events in patients with both ischemic and non-ischemic dilated cardiomyopathy (NIDCM). Various definitions and low specificity of fQRS, however, limited its use. We hypothesized that the advantage of 64-channel magnetocardiography (MCG), i.e., high spatio-temporal resolution, enables more accurate detection of fragmented LV conduction (fLV), that would lead to accurate prediction of future events.
Methods: In 51 patients with NIDCM and narrow QRS (LVEF, 22±7%; QRS duration, 99±11 ms), we recorded MCG. We defined, in MCG superimposed vector magnitude waveforms, fLV as distinct abnormal components (>20% of maximal amplitude). In current arrow map, fLV corresponded to heterogeneous QRS currents (Figure). We predicted major adverse cardiac events (MACE), including sudden cardiac death (SCD), sustained ventricular tachyarrhythmias (VF/VT), appropriate defibrillator discharge (Def) and left ventricular assist device implantation (LVAD).
Results: fLV was present in 27 (Group-F) and not in 24 (Group-N). Age, gender, ECG and echocardiographic findings, laboratory data and medications were similar irrespective of fLV. During a mean follow-up of 2.2 years, MACE occurred in 19 (4 SCD, 9 VF/VT, 2 Def, and 4 LVAD). MACE more frequently occurred with fLV (63%, 17/27) than without (8%, 2/24, Kaplan-Meier analysis, p<0.001). Multivariate analysis revealed fLV as the only independent predictor of MACE (HR 4.82, p=0.015).
Conclusion: MCG analysis is a promising noninvasive tool to accurately detect fragmentation and predict MACE in patients with NIDCM and normal QRS.
Author Disclosures: S. Kawakami: None. H. Takaki: None. S. Hashimoto: None. M. Wada: None. K. Ishibashi: None. I. Nakajima: None. K. Miyamoto: None. H. Okamura: None. T. Noda: None. T. Aiba: None. K. Kusano: None. S. Yasuda: None. H. Ogawa: None. S. Kamakura: None. M. Sugimachi: None.
- © 2014 by American Heart Association, Inc.