A new method for obtaining electrocardiograms in unrestrained crocodilian reptiles

A new procedure is described for acquiring measurements of electrocardiographic parameters in unrestrained crocodilians. These measurements are difficult to obtain in freely moving animals; hence, electrocardiographic activity under natural conditions has not been previously quantified. In this investigation, twelve American alligators were equipped with subcutaneous electrodes. The lead wires were sutured to each animal's skin and the extracutaneous wires coiled and held in place against the animals' dorsal surfaces with waterproof elastic bandages. The electrodes were connected to an ECG analyzer only at the time of measurement. The presence of the leads and harness did not appear to interfere with the movements of the animals either in the animal room or during testing. This method allows for more precise measurements of cardiac activity under conditions which closely resemble those of crocodilians in their natural state.