The transient outward potassium current plays a key role in spiral wave breakup in ventricular tissue
Julian Landaw, Xiaoping Yuan, Peng‐Sheng Chen, Zhilin Qu
Abstract
Spiral wave breakup manifesting as multiple wavelets is a mechanism of ventricular fibrillation. It has been known that spiral wave breakup in cardiac tissue can be caused by a steeply sloped action potential duration restitution curve, a property mainly determined by the recovery of L-type calcium current. Here, we show that the transient outward potassium current ( I to ) is another current that plays a key role in spiral wave breakup, that is, spiral waves can be stable for low and high maximum I to conductance but breakup occurs for intermediate maximum I to conductance. Since I to is present in normal hearts of many species and required for Brugada syndrome, it may play an important role in the spiral wave stability and arrhythmogenesis under both normal condition and Brugada syndrome.