Congenital sternal ectopia cordis in a Limousin calf – a case report

Recognition and detailed description of malformations and aberrations in domestic animals may be very useful in cognition of the problem and in creating breeding programs. The aim of this study was to describe a rare case of sternal (pectoral) ectopia cordis in a calf. A female calf of the Limousin breed born in Poland in 2011 was subjected to euthanasia because the heart was situated outside the chest. The carcass of the calf was subjected to anatomical examination in which alterations in cardiovascular system and in the structure of the sternum were observed. Cytogenetic studies were performed to find out if the karyotype of the calf was normal. Elongation of the ascending aorta was observed and the pattern of aortic branching was aberrant similarly to that found in dogs, not cattle. The systemic circulation was found to be linked to pulmonary circulation due to persisting large calibre arterial duct. Each of the ventricles had its own cardiac apex and walls of the ventricles manifested a similar width. The atria were slightly altered. A single, short and dilated blood vessel (pulmonary vein) evacuated its content to the left atrium. Pericardium formed no pericardial sac. Radiogram of the sternum demonstrated a ring-resembling shape and 12 (6 pairs) cartilaginous bars of the sternum (sternebrae). A normal female karytotype (60, XX) indicated that this malformation was not caused by an abnormal number of chromosomes (aneuploidy). Cattle, arterial pattern, sternum, chromosomes Ectopia cordis represents a developmental error involving the transposition of the heart outside the chest. Depending on the site to which displacement occurs, it is classified as cervical ectopia cordis (upper or lower ectopia), pectoral or sternal ectopia, and abdominal ectopia (Herzog and Wiedeking 1970; Shiran et al. 2010). Moreover, cases of thoracoabdominal and cervico-pectoral ectopia (Hiraga et al. 1990) were also reported. Manifestation of this developmental error has been detected in almost all livestock species (Hamali and Ashrafihelan 2010). However, vast majority of the reports of ectopia cordis concerned cattle (Wyrost and Radek 1982), and it was less frequent in horses (Hamali and Ashrafihelan 2010). Individuals affected by ectopia cordis in cattle died soon after birth or survived even several years, most frequently till maturity (Murakami et al. 1996). In this study we present a rare case of ectopia cordis of the pectoral (or sternal) type in a Limousin heifer. Materials and Methods Heart displacement (ectopia cordis) outside the chest was described in a newborn female calf of the Limousin breed born in Poland in 2011 on a commercial farm (birth weight 34 kg). The calf was the third offspring (all three female) of the cow and the delivery, similar to the preceding ones, took place by forces of nature. The sire of the calf was one of two bulls, since a harem mating system was followed on the farm. The calf proved to be viable and healthy, with a preserved sucking reflex. The heart, situated out of the chest, manifested a rhythmic pulsation of 132 contractions per minute. The owner of the farm decided on euthanasia which was performed by a veterinary surgeon by intravenous injection of pentobarbital 16 mg/kg (Morbital Biowet, Poland). The anatomical alteration of the heart was examined post mortem. Arteries were filled with stained LBS 3060 latex (650 ml injected into the left ventricle) and then the heart was fixed in 10% formalin and subjected to manual ACTA VET. BRNO 2014, 83: 051–054; doi:10.2754/avb201483010051 Address for correspondence: Nabzdyk Maria Poznań University of Life Sciences Department of Animal Anatomy, Institute of Zoology Wojska Polskiego 71c, 60-625 Poznań, Poland E-mail: [email protected] http://actavet.vfu.cz/ preparation. In order to facilitate inspection of cardiac cavities, the latex was removed from ventricles and atria. Using an electronic calliper, lengths and diameters of certain blood vessels were measured. The sternum was separated and its radiograms were prepared using the x-ray apparatus CR3X-PRO. Moreover, cytogenetic studies were performed to find out if the karyotype of the calf was normal. Chromosome preparations were obtained from fibroblast culture, derived from skin samples collected post mortem. The cells were cultured for 2 weeks and treated with colcemid solution followed by hypotonic treatment (0.075M KCl) and fixation (methanol:acetic acid, 3:1). Air dried microscopic slides were stained with Giemsa and analyzed under a Nikon E600 Eclipse microscope, equipped with a cooled digital CCD camera and computer-aided software LUCIA. International nomenclature of bovine chromosomes (Cribiu et al. 2001) was applied to analyze a karyotype of the studied case.