The assessment of electrophysiological indices and ECG parameters as predictors of fatal arrhythmias under ischemia/reperfusion setting in multivariate regression model.
Authors: Bernikova Olesya , Azarov Jan , Sedova Ksenia 
Published: June 2021

IntroductionThere are many factors predisposing to arrhythmia. The reentry mechanism is determined by dispersion of repolarization, unidirectional conduction block and activation slowing which can be documented as QRS widening. Similarly, the duration of repolarization and heart rate could favor the triggered activity or afterdepolarization proarrhythmic mechanism. The great interest for clinically application is the evaluation of noninvasive markers of fatal arrhythmias such as Tpeak‐Tend interval, QT dispersion and others but often they give unsatisfactory or conflicting results.The aim of the study was to find out which of the electrophysiological indices and ECG parameters contribute significantly to the genesis of fatal arrhythmias under experimental coronary occlusion and reperfusion using multivariate regression model.MethodsUsing needle plunge electrodes unipolar electrograms were recorded in intramural ventricular layers of 24 anesthetized open‐chest cats. Activation times (ATs) as dV/dt min during QRS, end of repolarization times (RTs) as dV/dt max during ST‐T, and activation‐recovery intervals (ARIs) as the time interval between the ATs and RTs were measured in total of 88 myocardial leads. The global, apicobasal, border RT dispersions were calculated as electrophysiological indices. The data were obtained at baseline, at 1 and 30 min of coronary occlusion and at 1 and 30 min of reperfusion.ResultsThe ventricular tachycardia and/or ventricular fibrillation (VT/VF) arose in a total of 10 animals at 1–5 minutes after reperfusion onset. During ischemia RTs progressively decreased and ATs increased in the ischemic zone and then progressively restored during reperfusion (P<0.05). The global, apicobasal, border dispersion of repolarization, QRS, Tpeak‐Tend intervals increased in all animals during ischemia and at the reperfusion onset (P<0.05). Under ischemia/reperfusion episode, the VT/VF group of animals demonstrated the greater global, border, apicobasal dispersion of RT, RTs in nonischemic and ischemic areas, QRS and Tpeak‐Tend intervals, and the lower heart rate as compared with the nonVT/VF animals (P<0.05). Using the multivariate logistic regression analysis we assessed the association between the dispersions of RT, RTs and ATs of ischemic and nonischemic zone under the 1 min of reperfusion and the occurrence of VT/VF. It was found that RTs of nonischemic zone (P=0.024) and global dispersion of RT (P=0.046) demonstrated significant association with the reperfusion VT/VF. The following ECG parameters as predictors of arrhythmias were tested (heart rate, Tpeak‐Tend, QRS and QTc intervals, Tpeak‐Tend/QT ratio). The QRS interval (P=0.01) and heart rate (P=0.009) were found to have the significant link with the occurrence of VT/VF.ConclusionThe multivariate regression model showed that the genesis of VT/VF was independently predicted by the repolarization duration in nonischemic area and the global dispersion of repolarization at the reperfusion onset. The QRS and heart rate were the independent ECG predictors of the occurrence of reperfusion VT/VF.Support or Funding InformationThe study was supported by the Program for Fundamental Research of RAS project № AAAA‐A17‐117012310154‐6, № AAAA‐A18‐118012290365‐2.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.