Magnetic Resonance Imaging (MRI) reveals high cardiac ejection fractions in red-footed tortoises (Chelonoidis carbonarius) [SHORT COMMUNICATION]

Catherine J. A. Williams, Eva M. Greunz, Steffen Ringgaard, Kasper Hansen, Mads F. Bertelsen, and Tobias Wang The ejection fraction of the trabeculated cardiac ventricle of reptiles has not previously been measured. Here we use the gold standard clinical methodology – electrocardiogram (ECG) gated flow magnetic resonance imaging (MRI) – to validate stroke volume measurements and end diastolic ventricular blood volumes. This produces an estimate of ejection fraction in the red footed tortoise Chelonoidis carbonaria (n=5) under isoflurane anaesthesia of 88±11%. After elimination of the prevailing right-to-left intraventricular shunt through the action of atropine, the ejection fraction was 96±6%. This methodology opens new avenues for studying the complex hearts of ectotherms, and validating hypotheses on the function of a more highly trabeculated heart than that of endotherms which possess lower ejection fractions.
Source: Journal of Experimental Biology - Category: Biology Authors: Tags: SHORT COMMUNICATION Source Type: research