Antemortem diagnosis of a ventricular septal defect in a California sea lion Zalophus californianus

Abstract

A yearling California sea lion Zalophus californianus stranded in poor body condition, and on physical examination a heart murmur was audible bilaterally. The sea lion was diagnosed with a left-to-right shunting membranous ventricular septal defect (VSD) using B-mode, color-flow Doppler and continuous-wave Doppler echocardiography. A left-to-right intracardiac shunting lesion was confirmed during cardiac angiographic computed tomography. The VSD defect was verified during the necropsy examination. On histologic examination concurrent mild multifocal myocarditis with focal mild ventricular free-wall myocardial necrosis were identified. A specific cause for the myocarditis and myocardial necrosis was not found, and association with the VSD and resultant myocardial dysfunction was presumed. This is the first report of the antemortem diagnosis of a VSD in a marine mammal and the first report of a VSD in a California sea lion. KEY WORDS: Echocardiography · Congenital defect · Cardiac disease · Heart disease · Ultrasound Resale or republication not permitted without written consent of the publisherDis Aquat Org 94: [83][84][85][86][87][88] 2011 to be left-to-right using color-flow Doppler ( Fig. 1) and continuous-wave Doppler. Both ventricles were subjectively dilated. Other cardiac structures were considered normal. Fractional shortening was calculated as 14.5% and ejection fraction as 31%. Heart rate was considered normal at 90 beats per minute (bpm). Published normal cardiac values for fractional shortening and ejection fraction for this species have not been published to the authors' knowledge.On observation of those echocardiogram findings, we obtained right lateral and ventro-dorsal radiographs of the thorax. Radiographs showed an enlarged cardiac silhouette with a calculated vertebral heart score (VHS) from the lateral radiographic view of 10.5 compared to the previously reported mean VHS of 8.65 (Dennison et al. 2009), and increased width on the ventro-dorsal view with the cardiac silhouette occupying 78% compared to the previous mean normal reported as 66% (Dennison et al. 2009). The pulmonary arteries and veins were symmetrical and enlarged compared to radiographs of other animals without evidence of cardiovascular disease, consistent with pulmonary over-circulation. A mixed bronchointerstitial to alveolar pattern was identified in all lung fields and was more apparent ventrally. These radiographic findings were most consistent with a left-toright shunting VSD and concurrent pneumonia and/or early cardiogenic pulmonary edema. The ventral distribution and lack of pulmonary venous distension was more consistent with pneumonia (aspiration, verminous or bacterial).Recovery from anesthesia was uneventful. Therapy for verminous pneumonia was started; it consisted of penicillin G procaine/penicillin G benzathine 1 ml per 10 kg intramuscular (i.m.) every other day (150 000 units of both penicillin forms in suspension; Pen BP-48, IVX Animal Health), carprofen 4.4 mg kg -1 once daily orally (100 mg chewab...

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).…”

Ventricular septal defect in a ferret (Mustela putorius furo)

“…The VSD to date has been described in several domesticated (Hamlin and others , Halnan , Knauer and others , Hawe , Donnelly and others , Vörös and others ) and non‐domesticated animals (Cook and others , Shinohara and Nishimura , Swindle and others , Johnson and others , Binhazim and others , Boon and others , Moore and others , Suedmeyer and others , Koie and others , Dennison and others ), including avian (Einzig and others , Harari and Miller , Bailey and Kinne ) and reptile (Brockman and Kennedy, ) species. In dogs, VSD has been found in conjunction with other cardiac defects in almost half of the cases (48%), usually pulmonic stenosis (65%)(Oliveira and others ).…”

Causes of mortality of harbor porpoises Phocoena phocoena along the Atlantic and Pacific coasts of Canada

“…Cardiac anomalies have been previously reported in marine mammals (Gray & Conklin 1974, Dennison et al 2011. Poor maternal condition, in utero viral infection, or exposure to toxin, as well as chromosomal and genetic alterations have been suggested as possible causes that are well described in humans (Schoen & Mitchell 2010).…”