Predictive value of unshielded magnetocardiographic mapping to differentiate atrial fibrillation patients from healthy subjects

• Published in: Annals of noninvasive electrocardiology Vol. 23; no. 6; pp. e12569 - n/a
• Main Authors: Guida, Gianluigi, Sorbo, Anna Rita, Fenici, Riccardo, Brisinda, Donatella
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01.11.2018; John Wiley and Sons Inc
• Subjects: Accuracy; Age Factors; Analysis of Variance; Angular speed; atrial fibrillation; Atrial Fibrillation - diagnosis; Atrial Fibrillation - diagnostic imaging; Body Surface Potential Mapping - methods; Cardiac arrhythmia; Case-Control Studies; Discriminant analysis; Dynamics; EKG; Electrocardiography - methods; Female; Fibrillation; Healthy Volunteers; Heart Atria - diagnostic imaging; Humans; Intervals; Inverse problems; inverse solution; Magnetic dipoles; Magnetic fields; magnetocardiography; Male; Mapping; Markers; Original; Parameters; Patients; Predictive control; Predictive Value of Tests; Prognosis; Quantitative analysis; Reference Values; Regression analysis; Retrospective Studies; Risk Assessment; Severity of Illness Index; Sex Factors; Signal Processing, Computer-Assisted; surface cardiac mapping; Wave dispersion; atrial fibrillation; discriminant analysis; surface cardiac mapping; inverse solution; magnetocardiography
• ISSN: 1082-720X; 1542-474X; 1542-474X
• DOI: 10.1111/anec.12569

Background P‐wave duration, its dispersion and signal‐averaged ECG, are currently used markers of vulnerability to atrial fibrillation (AF). However, since tangential atrial currents are better detectable at the body surface as magnetic than electric signals, we investigated the accuracy of magnetocardiographic mapping (MCG), recorded in unshielded clinical environments, as predictor of AF occurrence. Methods MCG recordings, in sinus rhythm (SR), of 71 AF patients and 75 controls were retrospectively analyzed. Beside electric and magnetic P‐wave and PR interval duration, two MCG P‐wave subintervals, defined P‐dep and P‐rep, were measured, basing on the point of inversion of atrial magnetic field (MF). Eight parameters were calculated from inverse solution with “Effective Magnetic Dipole (EMD) model” and 5 from “MF Extrema” analysis. Discriminant analysis (DA) was used to assess MCG predictive accuracy to differentiate AF patients from controls. Results All but one (P‐rep) intervals were significantly longer in AF patients. At univariate analysis, three EMD parameters differed significantly: in AF patients, the dipole‐angle‐elevation angular speed was lower during P‐dep (p < 0.05) and higher during P‐rep (p < 0.001) intervals. The space‐trajectory during P‐rep and the angle‐dynamics during P‐dep were higher (p < 0.05), whereas ratio‐dynamics P‐dep was lower (p < 0.01), in AF. At DA, with a combination of MCG and clinical parameters, 81.5% accuracy in differentiating AF patients from controls was achieved. At Cox‐regression, the angle‐dynamics P‐dep was an independent predictor of AF recurrences (p = 0.037). Conclusions Quantitative analysis of atrial MF dynamics in SR and the solution of the inverse problem provide new sensitive markers of vulnerability to AF.