Single-catheter multiple monophasic action potential recordings guided by electroanatomical magnetic source imaging

To validate a method for single-catheter multiple simultaneous monophasic action potentials recordings (MultiMAP), guided by three-dimensional (3D) magnetocardiographic electroanatomical source imaging (MEASI) Methods: MultiMAP was tested with sequential recordings from the epicardial surfaces of rats and guinea pigs and in 10 patients (pts). 4 MAPs were digitally recorded (DC-500 Hz, at 2 kHz, inter-MAP distance 1.2 mm). MAP duration at 90% and local conduction times were calculated. Cardiac magnetic field (MF) was mapped with 36-DC-SQUIDs. Atrial (AR) and ventricular repolarization (VR) estimate with MEASI and MultiMAP were compared. Results: MultiMAP evidenced local repolarization inhomogeneity and/or areas of slow conduction or focal block. MEASI estimate of AR was shorter than RAMAP duration, because of partial overlapping of ventricular MF. MEASI estimate of VR exceeded the RVMAP90%. Local ERP/MAP ratio ranged between 0,83 and 0.93. MultiMAP recording validated the accuracy of 3D MEASI of dominant frequency in pts with atrial fibrillation/flutter. Conclusion: MEASI provides 3D guiding of the MultiMAP on the arrhythmogenic substrate. MultiMAP recording is useful to detect local electrophysiologic abnormalities, to validate arrhythmogenic mechanisms before ablation and to guide focused endomyocardial biopsy.