Dear MARMAM members,
My co-authors and I are pleased to announce our recent publication on pinniped
hearts:
Rhea L. Storlund, David A.S. Rosen, Marco Margiocco, Martin Haulena, Andrew W.
Trites. 2021. Cardiac examinations of anesthetized Steller sea lions
(*Eumetopias justus*), northern fur seals (*Callorhinus ursinus*), and a walrus
(*Odobenus rosmarus*). Journal of Zoo and Wildlife Medicine, 52(2), 507-519.
DOI: 10.1638/2020-0054.
https://bioone.org/journals/journal-of-zoo-and-wildlife-medicine/volume-52/issue-2/2020-0054/CARDIAC-EXAMINATIONS-OF-ANESTHETIZED-STELLER-SEA-LIONS-EUMETOPIAS-JUBATUS-NORTHERN/10.1638/2020-0054.short
Abstract
Pinniped hearts have been well described via dissection, but in vivo
measurements of cardiac structure, function, and electrophysiology are lacking.
Electrocardiograms (ECGs) were recorded under anesthesia from eight Steller sea
lions (*Eumetopias jubatus*), five northern fur seals (*Callorhinus ursinus*),
and one walrus (*Odobenus rosmarus*) to investigate cardiac electrophysiology
in pinnipeds. In addition, echocardiograms were performed on all eight
anesthetized Steller sea lions to evaluate in vivo cardiac structure and
function. Measured and calculated ECG parameters included P-wave, PQ, QRS, and
QT interval durations, P-, R-, and T-wave amplitudes, P- and T-wave polarities,
and the mean electrical axis (MEA). Measured and calculated echocardiographic
parameters included left ventricular internal diameter, interventricular septum
thickness, and left ventricular posterior wall thickness in systole and
diastole (using M-mode), left atrium and aortic root dimensions (using 2D), and
maximum aortic and pulmonary flow velocities (using pulsed-wave spectral
Doppler). ECG measurements were similar to those reported for other pinniped
species, but there was considerable variation in the MEAs of Steller sea lions
and northern fur seals. Echocardiographic measurements were similar to those
reported for southern sea lions (*Otaria flavenscens*), including five out of
eight Steller sea lions having a left atrial to aortic root ratio <1, which may
indicate that they have an enlarged aortic root compared to awake terrestrial
mammals. Isoflurane anesthesia likely affected some of the measurements as
evidenced by the reduced fractional shortening found in Steller sea lions
compared to awake terrestrial mammals. The values reported are useful reference
points for assessing cardiac health in pinnipeds under human care.
Please email me at rstorlund at gmail.com for a PDF copy.
All the best,
Rhea Storlund
—
Rhea Storlund
PhD Candidate (Zoology)
Marine Mammal Research Unit
The University of British Columbia
Twitter: @RheaStorlund
Email: rstorlund at gmail.com
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