Meeting Abstract
American alligator hearts, despite having four chambers like birds and mammals and unlike most reptiles which have three, have not been well studied. In fact there is no literature about alligator heart action potential or calcium transient. Furthermore, although alligators live in a range of temperatures from 10°C to 30°C, little is known about the effect of temperature on their cardiac electrophysiology. With simultaneous voltage and calcium optical mapping at a resolution of 128×128 pixels and 500Hz, we present here the first detailed study of voltage and calcium dynamics in alligator hearts. Six Langendorff isolated alligator hearts were held at 20°C and 30°C and electrically stimulated. Surprisingly, we found that the action potential duration (APD) did not change much in comparison to mammalian hearts (e.g., rabbits and dogs) with varying temperature. Although we observed more pronounced dispersion of APD across the heart’s surface in comparison to mammalian hearts, we also observed less pronounced period doubling bifurcation in voltage and calcium dynamics at fast pacing cycle lengths. Our results indicate that alligators are well equipped to withstand large changes in body temperature without adverse effects in their electrical dynamics that could result in arrhythmia initiation.
