Controlled activation for interrogation of the electrophysiological substrate

Ectopic activation and conduction may give rise to arrhythmias when a diseased myocardial substrate exists. Electrophysiological mapping studies that record electrical properties of the heart in sinus rhythm may fail to uncover pro-arrhythmic substrates that are triggered by ectopy. In this study we use simulation and experimental models of clinical, trackable, loop catheters to interrogate regions of myocardium by stimulating and recording with multiple activation patterns. Longitudinal and traverse conduction velocities of the tissue were acquired from the pacing protocol. Artifacts resulting from variable distance between the recording electrodes and pacing site were also detected and removed. This study demonstrates that the mapping of local tissue properties with variable activation patterns is feasible and can expose features of the electrophysiological substrate that can not be recovered during sinus conduction.