Electrical Remodeling in the Epicardial Border Zone of the Human Infarcted Ventricle

The electrical and structural remodeling of the epicardial border zone (EBZ) after the infarct healing phase is related to an increased incidence of arrhythmias. Indeed, this remodeling affects the action potential duration (APD), refractoriness, vulnerability to conduction block, and conduction safety. Many studies have been undertaken to evaluate the effects of ionic remodeling in the border zone of the ischemic tissue, mainly in dogs and rabbits. In the present study, ionic remodeling in human ventricular cells was simulated applying changes to the model of human cardiac ventricular action potential proposed by O’Hara et al., to analyze the behavior of myocytes in the human EBZ. For this purpose, we introduced the ionic changes proposed by several experimental studies. We analyzed the APD of the remodeled cells, the behavior of the ionic currents, APD rate-adaptation, the action potential amplitude (APA), and finally we performed a sensitivity analysis to investigate the role of the remodeled ionic parameters in the alteration of the main electrophysiological characteristics. Our results show that after remodeling, APD increased by 44%, APD rate-adaptation was also significantly altered, as well as APA. These results are consistent with those obtained in other species. The sensitivity analysis showed that the conductance of the rapid delayed rectifier potassium current (G

Kr

) has a marked effect on the action potential duration at 90% repolarization (APD

90

), action potential at 30% repolarization (APD

30

), and AP triangulation; the changes in APA are mainly determined by the permeability of Ca

2 + 

(P

Ca

) and slightly by Na

 + 

channels conductance (G

Na

).