RESUMO
Herein we discuss modem data showing that ventricle's working myocardium is highly heterogeneous. Significant transmural differences in electrophysiological and biomechanical properties of cardiomyocytes are reviewed. The reviewed evidence of myocardial heterogeneity constitutes the basis for modem assessment of segmental kinetics of different regions in intact heart. We used muscle duplexes as condensed models of a heterogeneous myocardial system. Experimental data, presented here were obtained both in biological duplexes formed by isolated myocardial preparations and in mathematical models of muscle duplexes. We showed that specific functional heterogeneity of cardiomyocytes, related to their excitation sequence, allowed the myocardium to optimise its contractile function and smooth dispersion of repolarisation.
