Noninvasive, direct visualization of macro-reentrant circuits by using magnetocardiograms: initiation and persistence of atrial flutter

Abstract

Aims We analysed the cardiac magnetic fields on the body surface to visualize electrical currents noninvasively during reentrant arrhythmias.Methods and results Seven patients with counterclockwise atrial flutter (AFL) were studied during 17 episodes of AFL using 64-channel magnetocardiograms (MCGs) and electrophysiological study. Eight of the episodes were paroxysmal AFL, in which MCGs were recorded from the time of spontaneous onset to the time of termination. We constructed iso-magnetic field maps of the tangential components and produced MCG animations. With respect to AFL initiation, an atrial premature complex induced AFL. Prior to the initiation of AFL, atrial fibrillation (AF) transiently occurred. The cardiac magnetic fields revealed a single peak during sinus rhythm or with premature complexes but a disorganized pattern during AF. When AF transformed to AFL, the magnetic fields changed from a disorganized pattern to a single peak at first and then evolved to a circular pattern. During persistent AFL, the magnetic source moved in a counterclockwise circuit.Conclusion MCG animation can be used to visualize the sequence in which a premature complex transforms sinus rhythm to AFL via AF. Our findings indicate that MCGs can be used to identify noninvasively the mechanisms responsible for atrial tachyarrhythmias.

Construction of a Three-dimensional Outline of the Heart and Conduction Pathway by Means of a 64-channel Magnetocardiogram in Patients with Atrial Flutter and Fibrillation

“…The findings of Nakai et al confirm elegantly previous research suggesting that MCG resolution is good enough for non-invasive 3D functional imaging of atrial electrophysiology [3][4][5].…”

Magnetocardiography in Early Detection of Electromagnetic Abnormality in Ischemic Heart Disease

“…18) In addition, high time resolution of MCG (less than 5 ms) make visualization of the macro-reentrant circuits or microexcitations of atrial fibrillations, flutters, and atrial tachycardia possible. 38,39) In normal heart, the current arrow map during ventricular repolarization exhibits the single current pattern which indicates a leftward, inferior direction 40,41) (Figure 12). Hailer et al 42,43) reconstructed Upper panels: The change in magnetic field map angle after stress is greater in RCA patient than the control.…”

Magnetocardiograms in Clinical Medicine: Unique Information on Cardiac Ischemia, Arrhythmias, and Fetal Diagnosis

“…44 with multichannel recordings. Recent reports provide further evidence conforming MCGs as a practical useful tool for supplemental information in addition to other diagnostic modalities including ECGs (17)(18)(19)(20), so as to best take care of patients.…”

“…We animated MCGs by editing iso-magnetic field maps (the tangential components of the cardiac magnetic fields) with a minimal interval of 1 ms (17). The cardiac magnetic fields (red areas in Fig.…”