Temporal evolution of spatial regularity in ventricular fibrillation modified by physical exercise

This study analyses the modifications produced by physical exercise in cardiac mapping recordings during Ventricular Fibrillation (VF), compared to the ones produced by Glibenclamide. Three groups of rabbits were used. Gl: control (sedentary rabbits), G2: trained (rabbits submitted to a running program) and G3: drugged (sedentary rabbits treated with Glibenclamide). VF was induced during each experiment, and two recordings were acquired: maintained perfusion and ischemic damage. The recordings were analysed in consecutive 4-second segments and Regularity Index (RJ) was obtained for every segment and lead. RJ quantifies the morphological regularity among local activation waves found in a lead. A map with the RI value in each electrode was computed for each segment. In order to analyse the spatial distribution of RL Regions Of Interest (ROI) were obtained. Two parameters were calculated: ROI spatial number (ROlsn, a measure of spatial fragmentation), and ROI spatial area (ROlsa, the percentage of area map occupied by ROI). Control group has shown higher values of ROlsn than trained and drugged groups (p<;0.05) in both conditions (maintained perfusion or ischemic damage). Regarding ROlsa, control group had the lowest values (p<;0.05) in maintained perfusion, while these diferences where less marked with the presence of ischemic damage. On the contrary, no diferences were found between drugged and trained groups in any of the analysed parameters. The performed ROI analysis has shown that physical exercise and Glibenclamide decrease the fragmentation of VF cardiac response, increasing its spatial uniformity.