Role of extracellular potassium and cellular uncoupling on the electrical activity of the Purkinje-ventricle subsystem: A simulation study

Arrhythmias induced by phase 1B of ischemia are poorly understood. A bidimensional computer model has been developed to study the interaction between a bundle of Purkinje fibers and a layer of ventricular ischemic tissue. The present work has focussed on the role of the increase of extracellular potassium concentration and changes in the cellular coupling provoked by 1B ischemia in ventricular tissue connected to Purkinje fibers. To simulate 1B ischemic conditions, we altered several electro-physiological parameters of the Luo-Rudy action potential model(Lrd00). Our study suggests that a greater extracellular potassium concentration than 14.2 mmol/L and the moderate increase of cellular uncoupling induced by ischemia in a ventricular zone could cause conduction block in Purkinje to ventricle and conduction in ventricle to Purkinje, thus generating unidirectional block and reentry.