Pulmonary atresia with dextroposition of the aorta and ventricular septal defect in three Arabian foals.

The research paper discusses a rare case where three Arabian foal horses were diagnosed with a complex congenital heart anomaly, notably pulmonary atresia with dextroposition of the aorta coupled with a ventricular septal defect. This diagnosis was concluded after clinical evaluations and confirmed via necropsy following the animals’ euthanasia.

Initial Presentation and Diagnosis

• The study initially informs that three Arabian male foals were presented showing symptoms of cyanosis, a condition characterized by bluish or purplish discoloration of the skin due to lack of oxygen, heart murmurs, and exercise intolerance. These symptoms indicated the possibility of heart defects.
• A clinical evaluation was performed on the foals that suggested a preliminary diagnosis of a ventricular septal defect in conjunction with abnormalities of the major arteries.
• Given the severity of the condition and the poor prognosis, the owners of the foals request euthanasia.

Necropsy Findings and Final Diagnoses

• Post-mortem examination or necropsy was performed on the foals to ascertain the exact cause and nature of their heart defects. The results from the necropsies revealed the hearts of the foals to be noticeably identical with a large defect in the upper interventricular septum and malformations of the great arteries.
• The aorta of each heart was found to originate from an enlarged right ventricle and partially overlapped the ventricular septal defect. The point of origin of the aorta, the aortic ostium, was found to be guarded by three semilunar valvules. The positioning of these valves and the coronary artery openings were determined to be abnormal.
• The pulmonary arteries originated from a persistent ductus arteriosus and the pulmonary trunk was observed to be reduced to a thin fibrous cord extending from the constricted and abnormally short persistent ductus arteriosus to the semilunar valve, where it merged with the aortic wall. The pulmonary trunk, however, showed no connection with the right ventricular cavity.
• Based on all these findings, the research confirmed the final diagnosis to be pulmonary atresia with dextroposition of the aorta and ventricular septal defect.