Echocardiographic evaluation of four giant Aldabra tortoises (Aldabrachelys gigantea)

OBJECTIVES: In recent years echocardiography has become a good diagnostic tool in Zoo Medicine but in some cases, it is still a challenge. In Aldabra giant tortoise (Aldabrachelys gigantea) the big size of animals and the few individuals hosted in Zoo are critical points for the application of this diagnostic technique. The purposes of this research were: to evaluate the feasibility of the diagnostic imaging technique on big-sized turtles; to define the echographic parameters for this species; and to describe the morphofunctional and physiological echographic characteristics of their cardiovascular system. DESIGN: Repeated measures in vivo. SETTING: Ultrasonography systematic description and Doppler analysis of the cardiovascular system of Aldabra giant tortoise were carried out; B-mode examination allowed the evaluation of the kinetics of the ventricle, the atria and the atrioventricular valves. PARTICIPANTS: 4 Aldabra giant tortoises (two adult males and two young females) hosted in two zoological gardens. INTERVENTIONS: Echocardiography was performed placing the animals in ventral on a restraining platform raised from the floor, to provide adequate accessibility to the thoracic windows where the probe was placed. No chemical restraint was used. PRIMARY AND SECONDARY OUTCOME MEASURES: Heart rate, systolic and diastolic areas and volumes, vessel diameters and blood flow velocity were measured. RESULTS: Heart rate was 21±4 bpm (range 14–25 bpm). The averages of the diastolic and systolic area indexes linked to the subject weight were: 21±3 cm(2) and 9±1 cm(2). The aortic annulus diameter in female specimens measured 11.2±0.8 mm, while it measured 21.5±0.3 mm in male species. CONCLUSION: Results confirm the effectiveness of echocardiography as a means to study and evaluate the cardiovascular system of this species even if more studies on a bigger number of patients would be necessary to develop the echocardiography technique.