Role of myocardial ischemia components in overdrive pacing of spiral waves

Abstract

Dangerous cardiac arrhythmias occur often due to ischemic heart disease. One of the most important methods for removing an arrhythmia is low-voltage electrotherapy, in particular overdrive pacing, that is stimulation from an implanted cardioverter with a period slightly less than the arrhythmia period. The main aim of this paper is to study how ischemia can affect overdrive pacing of arrhythmias caused by rotating spiral waves. We performed simulations using the ten Tusscher–Panfilov 2006 model for human cardiac tissue and studied how specific components of ischemia, such as hyperkalemia, hypoxia and acidosis, affect the dynamics of spiral waves and overdrive pacing. The hyperkalemia increased the spiral wave period more than twofold and caused meandering. Hypoxia slightly decreased the period. Acidosis caused meandering and spontaneous drift, which can result in the disappearance of spiral waves. Overall, the ischemia increased the efficiency of overdrive pacing, an effect that was mainly due to hyperkalemia.