Multimodal integration of MAP recordings and MCG imaging in patients with paroxysmal atrial arrhythmias, using the MultiMAP amagnetic catheter

The amagnetic catheter (AC) for simultaneous, high resolution, atrial mapping of multiple monophasic action potentials (Multi-MAP), has been clinically tested in patients with paroxysmal atrial fibrillation, flutter, or focal tachycardia. As previously demonstrated, the 6F AC for MultiMAP recording and local pacing can be also localized, without fluoroscopy by multichannel magnetocardiographic mapping (MMCG) with a 3D accuracy of 2-7 mm. In this study MMCG was used to localize the AC in our unshielded laboratory, during minimally invasive electrophysiologic study. MMCG was performed with a 9channel system (CMI, USA), before and/or during the invasive EP study. 4 MAPs were recorded from an area of about 3.5 mm2, during sinus rhythm (SR), atrial pacing and pacing-induced atrial arrhythmias. MAP signals were differentially amplified, bandpass filtered (DC-500 Hz) and digitized at the sampling frequency of 1-2 kHz (GE-Prucka Cardiolab). MAP duration at 90% levels of repolarization and local conduction times between the phase 0 of the four MAPs were calculated. To evidence local repolarization inhomogeneity and/or areas of slow conduction or focal block. In spite of unfavorable signal to noise ratio, as compared to shielded room, the tip of the AC was localizable with MMCG also in the unshielded EP laboratory. In patients with paroxysmal atrial arrhythmias, the novel MMCG-guided multi-MAP recording technique can be useful to detect with minimal invasivity, local electrophysiological abnormalities, not evidenced by standard EP catheters and filtered recording