Dear marmers, We are proud to announce our new publication in cardiac function in bottlenose dolphins published in Journal of Experimental Biology.
Title: Evaluating cardiac physiology through echocardiography in bottlenose dolphins: using stroke volume and cardiac output to estimate systolic left ventricular function during rest and following exercise Authors: Stefan Miedler, Andreas Fahlman, Mónica Valls Torres, Teresa Álvaro Álvarez, Daniel Garcia-Parraga Journal: Journal of Experimental Biology 2015 218: 3604-3610; doi: 10.1242/jeb.131532 Abstract: Heart-rate (fH) changes during diving and exercise are well documented for marine mammals, but changes in stroke volume (SV) and cardiac output (CO) are much less known. We hypothesized that both SV and CO are also modified following intense exercise. Using transthoracic ultrasound Doppler at the level of the aortic valve, we compared blood flow velocities in the left ventricle and cardiac frequencies during rest and at 1, 3 and 4 min after a bout of exercise in 13 adult bottlenose dolphins (Tursiops truncatus, six male and seven female, body mass range 143–212 kg). Aortic cross-sectional area and ventricle blood velocity at the aortic valve were used to calculate SV, which together with fH provided estimates of left CO at rest and following exercise. fH and SV stabilized approximately 4–7 s following the post-respiratory tachycardia, so only data after the fH had stabilized were used for analysis and comparison. There were significant increases in fH, SV and CO associated with each breath. At rest, fH, SV and CO were uncorrelated with body mass, and averaged 41±9 beats min−1, 136±19 ml and 5514±1182 l min−1, respectively. One minute following high intensity exercise, the cardiac variables had increased by 104±43%, 63±11% and 234±84%, respectively. All variables remained significantly elevated in all animals for at least 4 min after the exercise. These baseline values provide the first data on SV and CO in awake and unrestrained cetaceans in water. For reprints please e-mail Andreas Fahlman: [email protected]<mailto:[email protected]> or download at: http://jeb.biologists.org/jexbio/218/22/3604.full.pdf Andreas Fahlman Department of Life Sciences Texas A&M- Corpus Christi 6300 Ocean Dr Unit 5892 Corpus Christi, TX 78412 Ph. +1-361-825-3489 Fax +1-361-825-2025 mail: [email protected]<mailto:[email protected]> web: http://www.comparative-physiology.tamucc.edu/
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