Foramen Ovale and Ductus Arteriosus Patency in Neonatal Harbor Seal (Phoca vitulina) Pups in Rehabilitation

Abstract

Twenty neonatal harbor seal (Phoca vitulina) pups in rehabilitation following maternal separation underwent serial echocardiographic studies to assess patency and subsequent age of functional closure of the ductus arteriosus (d.a.). B-mode, color-flow Doppler, and pulse and continuous wave Doppler were utilized to identify the d.a. and determine patency and directionality of blood flow. Seals were also evaluated for evidence of foramen ovale (f.o.) patency. B-mode ultrasound was used to evaluate the inter-atrial septum for abnormal (aneurismal) motion, a sign of f.o. patency in other species. In one harbor seal, this motion was confirmed as being consistent with f.o. patency by contrast echocardiography. Closure of the f.o. was not confirmed in any harbor seal prior to release back into the free-ranging population.Data acquired indicate that there is patency of the f.o. and d.a. after birth for a longer period in phocids than in described terrestrial mammals.

Pinnipediae

“…There is parenchymal collapse, neuronal loss throughout the dentate gyrus (DG) and cornu ammonis (CA) sectors 1-4, and gliosis. may be functional patency of the foramen ovale and ductus arteriosus up to 6-7 weeks of age, therefore, these should not be considered congenital defects in very young pups without additional evidence of cardiac disease ( Dennison et al, 2011). In elephant seals, hydrocephalus and cardiac abnormalities are most common.…”

Echocardiographic Left Ventricular Structure and Function in Healthy, Non-Sedated Southern Sea Lions (Otaria flavescens)

“…Cardiac abnormalities and diseases have been reported postmortem in marine mammals such as northern elephant seals (Mirounga angustirostris), pygmy sperm whales (Kogia breviceps), bottlenose dolphins (Tursiops truncatus), northern fur seals (Callorhinus ursinus), dwarf sperm whales (Kogia sima), Florida manatees (Trichechus manatus latirostris), and southern sea otters (Enhydra lutris) (Trupkiewicz et al, 1997;Kreuder et al, 2003;Bossart et al, 2007;Powell et al, 2009;Spraker & Lander, 2010;Gerlach et al, 2013). Only a few studies have achieved the in vivo diagnosis of heart abnormalities in marine mammals through echocardiography such as the foramen ovale and ductus arteriosus patency found in neonatal harbor seals (Phoca vitulina; Dennison et al, 2011a) or the ventricular septal defects found in a harbor porpoise (Phocoena phocoena; Szatmári et al, 2016) and California sea lions (Zalophus californianus; Dennison et al, 2011b).…”

Congenital Diseases in Harbor Seals (Phoca vitulina richardsii) from the Salish Sea

“…Several heart defects were noted, including a ventricular septal defect, mitral valvular dysplasia with associated hydrothorax, myocardial fibrosis, and mitral valvular thickening. Patent foramen ovale were noted in two weaned pups and one yearling, animals older than expected for persistent fetal circulation (Dennison et al 2011).…”