Influence of ischemia and reperfusion duration on left ventricular depolarization in isolated rabbit hearts registered by optical method

The influence of ischemia and reperfusion duration on left ventricular depolarization is studied from electrograms (ECG) and monophasic action potentials (MAPs) recorded by optical method. Left ventricular depolarization is evaluated by activation time (AT), which is defined as the distance from the earliest QRS deflection to the MAP upstroke and which describes time duration of depolarization propagation. The excitement conduction in ischemic heart takes longer time in comparison to non-ischemic myocardium. Speed of impulse conduction decreases with ongoing ischemia, and thus the activation time increases proportionally to ischemia duration. During reperfusion, speed of impulse conduction increases immediately with the first minute of reperfusion and remains at the same value till the end of examined period.