[Excitation conduction in the rat pulmonary veins myocardium assessed by the optical mapping]

In this study, conduction of excitation in the rat left atrial and pulmonary veins myocardium was assessed by the optical mapping technique. Rat atrial myocardium and pulmonary vein myocardium demonstrated weak differences in the activation time and conduction velocity. Maximal conduction velocity in atrial myocardium estimated by the optical mapping was 84 +/- 14 cm/s, the same parameter in pulmonary vein myocardium was 71 +/- 11 cm/s. Period of refractoriness in the atria was significantly shorter (44 +/- 3 ms) than in pulmonary vein myocardium (60 +/- 3 ms). Despite the differences in the period of refractoriness excitation wavelength in the pulmonary veins and atrial myocardium was very similar (43 +/- 7 and 37 +/- 5 mm, respectively). Conduction of excitation in rat atria was characterized by high level of "linearity". Regions with essential decrease of conduction velocity and complete abruption of conduction (conduction blocks) were observed in pulmonary vein myocardium. It was suggested that high histological heterogeneity and intercellular electrical resistance played an important role in conduction abnormalities in rat pulmonary veins.