14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-123

New multipurpose amagnetic catheter and method for non-fluoroscopic high resolution monophasic action potential mapping guided by magnetic source imaging (MSI)

Riccardo Fenici, Donatella Brisinda, Maria Pia Ruggieri, Peter Fenici.
Clinical Physiology, Biomagnetism Research Center, Catholic University, Rome, Italy

Abstract

BACKGROUND. An advanced development of the amagnetic catheter (AC) for magnetocardiographically guided intracardiac electrophysiological recordings and ablation of cardiac arrhythmias is described, which allows single catheter recording of four monophasic action potentials (MAP) simultaneously (Multi-MAP function).

METHODS. The 6F AC features five non-polarizable amagnetic electrodes, arranged in such a way that orthogonal or parallel current dipoles can be generated in the patients heart. This assembly can be localized by Magnetic Source Imaging (MSI), with a three-dimensional (3D) accuracy of 2-7 mm, without the use of fluoroscopy. On the basis of preoperative MCG 3D localization, the AC can be driven, under fluoroscopic control, as close as possible to the arrhythmogenic zone. Once reached the area of onset of the arrhythmia the tip electrodes are used to record simultaneously four MAPs from an area of about 4 mm². Alternatively two electrodes can be used for local pacing and two simultaneous MAP recordings. MAP signals are differentially amplified, bandpass filtered (DC-1kHz) and digitized at the sampling frequency of 2-4 kHz. MAP duration at 50 and 90% levels of repolarization and local conduction times between the phase 0 of the four MAPs are automatically calculated with a custom software.

RESULTS. With this AC, the average amplitude of right atrial MAP (10 patients) was 6.2±2.4 mV and that of the right ventricular (RV) MAP (15 patients) was 23±9 mV. Local variation coefficients of RV MAP duration at 50 and 90% level of repolarization were 7.4 and 3.1%, respectively. Local repolarization inhomogeneity and of areas of slow conduction or focal block were detected with the multi-MAP recording technique.

CONCLUSION. This new multi-MAP AC in combination with MSI, provides non fluoroscopy-dependant single-catheter high resolution intracardiac mapping of local electrophysiological abnormalities from MSI predefined arrhythmogenic areas.

Key Words