Effect of sodium inward current on extracellular potassium accumulation during myocardial ischemia: a simulation study

Myocardinal ischemia leads to extracellular potassium accumulation (/spl Delta/[K/sup +/]/sub o/) and, as one of its consequences, to the development of reentrant arrhythmias, a major cause of sudden cardiac death. Subsequently, much attention has been paid to the study of mechanisms that could contribute to /spl Delta/[K]/sub o/ in ischemic myocytes. Nevertheless, the causes of this phenomenon are still poorly understood. Na-related mechanisms have been proposed as been in part responsible for the ischemic increase of K/sup -/ efflux. The authors of this paper incorporated a constant Na current of -1 /spl mu/A//spl mu/F to the Luo-Rudy phase II action potential model. This modified version was used to simulate the electrical behavior of cardiomyocytes in the absence of coronary flow. The authors' results show that the enhancement of Na influx leads to fast /spl Delta/[K]/sub a/ of 3.8 mmol/L.