Effects of potassium channel openers nicorandil and pinacidil on electrical activity of cardiac cells and cardiac tissues: a simulation study

Potassium channel openers (KCOs) have been reported to activate ATP-sensitive potassium channels (K/sub (ATP)/) in cardiac muscle. The activation of this current accelerates the process of repolarisation of the cell and shortens the action potential duration (APD). In this study the authors analyse whether this effect is proarrhythmic or not. Indeed, there is a big controversy; in this sense supported by several studies. Based on experimental data, the authors formulated a mathematical description of the effects of two KCOs (pinicidil and nicorandil) on the ATP-sensitive potassium current. These models were introduced in a ventricular myocyte action potential description to carry out unicellular and multicellular simulations. Our results suggest that pinacidil shortens APD further than nicorandil, as reported in several experimental works. In a cellular tissue, both drugs increase the probability of unidirectional block and thus reentry.