Influence of 1B ischemic ventricular tissue on the automaticity of Purkinje fibers: A simulation study

A computer model has been developed to study the electrical activity of a Purkinje fiber of 1.5 cm coupled to a regionally 1B ischemic ventricular fiber of 3 cm through a Purkinje-muscle resistance (R_pvj). The ventricular fiber was composed of a 1B ischemic zone, a border zone and a normal zone of 1 cm each. To simulate ischemia, we altered several electrophysiological parameters of the Luo-Rudy action potential model (Lrd00). The aim of this study was to investigate the influence of 1B ischemic ventricular tissue on the automaticity of Purkinje cells and its role in ectopic activity that could provoke arrhythmias. Our study suggests that 1B ischemic ventricular tissue enhances automaticity of Purkinje fibers and could have an important role on the generation of ectopic action potentials near the Purkinje-muscle junctions. This phenomenon may be involved in the generation of ectopic activity and cardiac arrhythmias.