Key result
Simulated acute ischemia shortens action potentials and induces diastolic depolarization via increased IK1 current.
Why the study?
The effects of acute myocardial ischemia on the electrical and mechanical function of cardiomyocytes were studied using a mathematical model to understand ionic current contributions.
Computational modeling demonstrates that increased extracellular potassium during acute ischemia primarily shortens action potential duration via the inward rectifier potassium current I(K1).
Hypothesis-generating for I(K1) in ischemic arrhythmias; requires in vivo validation before clinical consideration.
The effect of acute myocardial ischemia on the electrical and mechanical function of cardiomyocytes was studied in the framework of a mathematical model of a single cardiomyocyte. Acute ischemia consequences were simulated via a combination of two factors--a reduction of intracellular ATP concentration and an increase in extracellular potassium concentration, which affect the kinetics of ATP-sensitive potassium current and other potassium currents. In accord with experimental data, ischemic models produce action potential shortening and diastolic depolarization, which reduce contractile, ability of cardiomyocytes, Utilizing a 'difference-current integral' approach, we assessed quantitative contribution of ionic currents to changes in the action potential generation during ischemic injuries. It has been shown that an increase in the amplitude of inward rectifier potassium current I(K1) with increased extracellular potassium concentration has most essential contribution to the changes in the action potential duration under ischemia.
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Balakina-Vikulova et al. (2014) studied Acute myocardial ischemia. Simulated acute ischemia (reduced intracellular ATP and increased extracellular potassium) was evaluated on Changes in action potential generation and duration. Simulated acute ischemia produced action potential shortening and diastolic depolarization, with increased amplitude of inward rectifier potassium current I(K1) contributing most to these changes.
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