Myocardial ischemia: what factors determine arrhythmogenesis?

In ischemic myocardium, cellular architecture and heterogeneous changes in metabolic and ionic conditions interact to cause spatial and temporal heterogeneity of electrical properties predisposing to lethal ventricular arrhythmias. Yet, the details of their interaction, vis-à-vis the initiation and maintenance of reentry, remain poorly understood. Future studies are needed to address the mechanisms of the initial premature beat, reentry, and formation of wavebreaks contributing to ventricular fibrillation. New experimental methods including mathematical and transgenic mouse models are promising techniques to study these phenomena and thereby provide new insights into the fundamental mechanisms of ischemia-related arrhythmias.