Electrocardiographic Markers of Cardiomyocytes’ Action Potentials Lengthening in the Border Zone of Ischemia (Experimental and Model Study)

Background : Ventricular fibrillation within the first 5 min of reperfusion was observed in the animals with lengthening but not shortening of action potential duration (APD) in the border zone of ischemia. Objective : The objective of the study was to find the electrocardiographic manifestations of the APD changes in the border zone of ischemia as the markers of ventricular fibrillation. Design and methods : The simulations were carried out using the model of the cat heart ventricles. To simulate the ischemia, we decreased activation velocity and modified the durations and the amplitudes of action potentials. Results : The simulations showed that APD’s increase in the border zone of ischemia was detectable in the ECG leads most proximal to the heart (V2,V3). It was manifested by the T-wave lengthening and the change of its polarity in the terminal period of repolarization. The similar T-wave features were observed in the electrograms of cats with the reperfusion ventricular fibrillation Conclusion : The simulation data can be useful for the development of new methods of diagnostics of the most dangerous types of ischemia associated with ventricular fibrillation.