Activation fronts elicited remote to the pacing site due to the presence of scar tissue

Endocardial pace mapping is a technique used clinically to identify slow conduction pathways in reentrant circuits produced by healed myocardial infarction. This computational model of embedded scar tissue in viable myocardium was developed to study activation patterns resulting from extracellular pacing stimuli. Bipolar stimulation was applied in the bounding blood volume near the scar tissue at different strengths and durations. Redistribution of current between the intracellular and interstitial spaces due to the presence of scar tissue caused regions of hyperpolarization and depolarization sufficient to elicit wavefronts extraneous to that expected nearest the cathode. These extraneous fronts are misleading in the interpretation of the stimulus to QRS interval that is used to identify the slow conduction pathways