caa a22 4500 465826474 CHVBK 20180323112150.0 cr unu---uuuuu 170327e19900801xx s 000 0 eng 10.1007/BF00302591 doi (NATIONALLICENCE)springer-10.1007/BF00302591 Cardiac function of the leopard shark, Triakis semifasciata [Elektronische Daten] [N. Chin Lai, Ralph Shabetai, Jeffrey Graham, Brian Hoit, Katharina Sunnerhagen, Valmik Bhargava] Summary: The pressure difference between the cardinal sinus and the pericardium, and the transmural ventricular diastolic pressure at rest and during swimming in the leopard shark, Triakis semifasciata, was measured to characterize the mechanism of cardiac filling in chronically-instrumented fish and to evaluate cardiac responses to swimming. Echo-Doppler and radiographic imaging were also used to fully describe the cardiac cycle. Swimming induces an increase in preload as manifested by a large increment of cardinal sinus pressure (0.26/0.20 [systolic/diastolic] to 0.49/0.32 kPa) which always exceeds pericardial pressure. Increases in both mean ventricular diastolic transmural pressure (0.30-0.77 kPa) and cardinal sinus pressure during swimming suggest increased cardiac filling by vis a tergo as the mechanism for augmenting cardiac output. In contrast to mammals, the fluid-filled pericardial space of elasmobranchs is considerably larger and the pericardium itself does not move in concert with the heart throughout the cardiac cycle. Also, modest increases in heart rate drastically curtail the duration of diastole, which becomes much less than that of systole, a phenomenon not found in mammals. In the absence of tachycardia (<40 bpm), ventricular filling is characterized by a period of early rapid filling, and a late period of filling owing to atrial systole, separated by a period of diastasis. Ventricular filling in elasmobranchs is thus biphasic and is not solely dependent on atrial systole. Atrial diastole is characterized by three filling periods associated with atrial relaxation, ventricular ejection, and sinus venosus contraction. The estimated ventricular ejection fraction of Triakis (80%) exceeds that of the mammalian left ventricle. Springer-Verlag, 1990 Triakis semifasciata nationallicence Swimming nationallicence Transmural pressure nationallicence Echocardiography nationallicence Angiocardiography nationallicence Chin Lai N. Physiological Research Laboratory, A-004, Scripps Institution of Oceanography, University of California, San Diego, 92093, La Jolla, CA, USA aut Shabetai Ralph Department of Medicine, University of California, San Diego, 92161, San Diego, CA, USA aut Graham Jeffrey Physiological Research Laboratory, A-004, Scripps Institution of Oceanography, University of California, San Diego, 92093, La Jolla, CA, USA aut Hoit Brian Division of Cardiology, University of Cincinnati Medical Center, M.L. 542, 45267, Cincinnati, OH, USA aut Sunnerhagen Katharina Department of Medicine, University of California, San Diego, 92161, San Diego, CA, USA aut Bhargava Valmik Department of Medicine, University of California, San Diego, 92161, San Diego, CA, USA aut Journal of Comparative Physiology B Springer-Verlag 160/3(1990-08-01), 259-268 0174-1578 160:3<259 1990 160 360 https://doi.org/10.1007/BF00302591 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00302591 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chin Lai N. Physiological Research Laboratory, A-004, Scripps Institution of Oceanography, University of California, San Diego, 92093, La Jolla, CA, USA aut NATIONALLICENCE 700 1- Shabetai Ralph Department of Medicine, University of California, San Diego, 92161, San Diego, CA, USA aut NATIONALLICENCE 700 1- Graham Jeffrey Physiological Research Laboratory, A-004, Scripps Institution of Oceanography, University of California, San Diego, 92093, La Jolla, CA, USA aut NATIONALLICENCE 700 1- Hoit Brian Division of Cardiology, University of Cincinnati Medical Center, M.L. 542, 45267, Cincinnati, OH, USA aut NATIONALLICENCE 700 1- Sunnerhagen Katharina Department of Medicine, University of California, San Diego, 92161, San Diego, CA, USA aut NATIONALLICENCE 700 1- Bhargava Valmik Department of Medicine, University of California, San Diego, 92161, San Diego, CA, USA aut NATIONALLICENCE 773 0- Journal of Comparative Physiology B Springer-Verlag 160/3(1990-08-01), 259-268 0174-1578 160:3<259 1990 160 360 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer