Validation of Transthoracic Anatomic M-mode Echocardiography in the Bottlenose Dolphin (Tursiops truncatus)
Jonathan Lichtenberger1, DVM; Mathieu Mellin2, DVM; Birgitta Mercera2; Fabienne Delfour2, PhD; Anne-Cécile Hoffmann1, DVM; Emilie Trehiou-Sechi1, DVM; Gwendoline Chaix1, DVM; Charlotte Misbach1, DVM; Amandine Petit1, DVM; Nicolas Gaide1, DVM; Hervé Lefebvre3, DVM, PhD; Renaud Tissier4, DVM, PhD; Valérie Chetboul1,4, DVM, DECVIM-CA, PhD
1Unité de Cardiologie d’Alfort, Ecole Nationale Vétérinaire d’Alfort, Maisons-Alfort, France; 2Delphinarium du Parc Astérix, Parc Astérix, Plailly, France; 3Unité de Recherche Clinique Santé des Populations, Ecole Nationale Vétérinaire de Toulouse, Toulouse, France; 4UMR INSERM, Ecole Nationale Vétérinaire d’Alfort, Maisons-Alfort, France
Abstract
The use of transthoracic echocardiography to evaluate the dolphin heart has been limited so far because of technical and anatomic specificities.1,2 Anatomic M-mode (AMM) is an echocardiographic technique capable of generating M-mode studies from two-dimensional (2D) cine loops independently of the ultrasound beam orientation. The aim of the present study was to determine the within-day (repeatability) and the between-day (reproducibility) variability of AMM in awake healthy bottlenose dolphins (BN, Tursiops truncatus).
Four healthy BN (9–31yr; 180–250 kg) trained to lie in left lateral recumbency were included. A total of 96 echocardiographic examinations were performed using a Vivid i system (GE Medical System, Waukesha, WI, USA) equipped with a 3.5 MHz phased-array transducer by the same trained observer on 4 different days over a 2-week period with 4 dolphins examined 6 times/day. Video clips of 2D left parasternal long-axis views showing the left ventricle (LV) ventrally and the aortic root dorsally were recorded at each examination and analyzed on the same day for AMM measurements. A general linear model was used to determine the within-day and between-day coefficients of variation (CV).
All examinations were interpretable allowing calculation of 10 AMM variables (i.e., end-diastolic and end-systolic ventral and dorsal LV myocardial wall thicknesses, LV and aortic diameters, mean aortic diameter, and LV shortening fraction). Most within- and between-day CV values (16/20) were <10%, the lowest being observed for the end-diastolic LV diameter (1.6%).
Conclusion
AMM provides a simple non-invasive evaluation of left heart morphology and function in BN with good repeatability and reproducibility.
Acknowledgments
The authors thank all the dolphins’ trainers of the Parc Astérix dolphinarium (Plailly, France) for their technical assistance and Scil Animal Care Company for providing the Vivid i system.
Literature Cited
1. Brook, F., W. Van Bonn, and E. Jensen. 2001. Ultrasonography. In: Dierauf L. A. and F. M. D. Gulland (eds.). CRC Handbook of Marine Mammal Medicine. CRC Press, Boca Raton. 593–620.
2. Sklansky M., G. Levine, D. Havlis, N. West, M. Renner, C. Rimmerman, and R. Stone. 2006. Echocardiographic evaluation of the bottlenose dolphin (Tursiops truncatus). J Zoo Wildl Med. 37:454–463.