An unusual presentation of developmental anomalies of the cardiovascular system including tetralogy of fallot, double outlet right ventricle, patent foramen ovale and persistent right aortic arch in a Friesian calf

Abstract

Background: Congenital heart diseases are occasionally encountered in the bovine species. Ventricular septal defects (VSD) and atrial septal defects (ASD) are reported to be the most common; however, a vast collection have been reported [1, 2]. Congenital heart diseases is thought to represent less than 3% of all congenital abnormalities in calves [3]. Various cardiac anomalies arise due to defective embryologic development such as defects of the septae or the cardiac chambers [2]. The exact aetiology of these congenial heart anomalies remains to be fully elucidated [4]. VSDs appear to be the most common congenital cardiac anomaly in calves. Other diseases can be subdivided into cyanotic (e.g. ASD or patent ductus arteriosus) and non-cyanotic (e.g. tetralogy of fallot or eisenmengers complex) [5, 6]. An exceptional presentation of an array of congenital anomalies was identified in a Friesian heifer calf. To the authors' knowledge this concurrent collection of congenital abnormalities has never been reported in this species. Case presentation: A 3-day old Friesian heifer presented with a history since birth of regurgitation post feeding. The main finding on clinical examination was tachypnoea with a holosystolic murmur. Echocardiography identified a VSD, patent foramen ovale (PFO) (both with left to right blood flow) and tricuspid insufficiency. The calf was subsequently euthanised and underwent gross post-mortem examination. A persistent right aortic arch (PRAA) was identified. The cardiac anomalies identified on the echocardiogram were confirmed along with additional abnormalities; double outlet right ventricle (DORV), partial transposition of the great vessels, pulmonic stenosis, hypoplasia of the right branch of the pulmonary artery and right ventricular hypertrophy. The final diagnosis was Tetralogy of Fallot with DORV, PFO and PRAA. The lungs appeared oedematous and congested due to cardiac malfunction and cranioventral aspiration pneumonia. Free serous fluid was identified in the thoracic cavity. Unilateral renal agenesis of the left kidney was an incidental finding but is of note due to its coexistence with the cardiac abnormalities.

Double-Outlet Right Ventricle in a Chianina Calf

“…The incidence of DORV in domestic animals is rare and only few case reports have been reported in cats, dogs, horses, pigs, alpacas, and calves [ 6 , 7 , 21 , 27 , 28 , 29 , 30 , 31 ]. This complex congenital cardiac malformation has been only described in Angus, Brangus, Herford and Holstein breeds [ 6 , 7 , 8 , 9 , 10 ]. To the best of our knowledge, the present report describes for the first time this complex cardiac malformation in a Chianina calf.…”

“…Anatomically, DORV must be associated with any of the right to left communications (ASD, VSD, patent ductus arteriosus (PDA) or a combination of the former) to allow arterial and venous blood to mix and deliver oxygen to peripheral tissues. In the reported cases of bovine DORV, a various combination of shunting was present, the most common being represented by VSD that were either large or double, accounting for the shunting of blood [ 7 , 8 , 9 , 10 ]. DORV in the absence of VSD is very rare both in humans and animals and accounts for only one of the reported bovine cases [ 6 ].…”

“…The double-outlet right ventricle (DORV) is a rare congenital ventriculoarterial malformation where both arterial trunks emerge from the right ventricle. This complex cardiac anomaly has been described only in certain cattle breeds [ 6 , 7 , 8 , 9 , 10 ], but it has never been reported in the Chianina breed.…”

A germline de novo variant in NUMB associated with a double‐outlet right ventricle in Chianina cattle

“…Congenital heart disease (CHD) comprises a wide spectrum of abnormalities in heart structure that occur in the fetus during pregnancy (Sun et al, 2015). Double‐outlet right ventricle (DORV) is a rare form of ventriculoarterial connection reported in a few cattle breeds (Caivano et al, 2021; McManus et al, 2020; Newhard et al, 2017; Nourani et al, 2009; Prošek et al, 2005; Wilson et al, 1985). However, the etiology of DORV in cattle has not yet been clarified.…”