Pulmonary atresia with intact ventricular septum and hypoplastic right ventricle in an Arabian foal

Ascending aortic aneurysm associated with tetralogy of Fallot in an adult mare

“…Congenital heart disease (CHD) represents the outcome of errors during fetal cardiac development (Scansen, 2019). The reported prevalence of 0.1%–0.5% for congenital cardiac defects in horses is relatively low as compared with other animals (Hall, Magdesian, & Kitt, 2010; Kruger, Wunschmann, Ward, & Stauthammer, 2016). Such defects have usually a profound impact on the foals through altered growth rate, exercise intolerance, respiratory distress and death (Hall et al., 2010; Scansen, 2019).…”

Congenital heart defects in Arabian horses and the prospects of genetic testing: A review

“…30 Isolated cases of PDA are uncommon in horses, and thus the clinical signs of PDA are difficult to separate from those caused by concomitant defects. [5][6][7][8][9]16,30 In rare cases, shunt reversal can occur due to prolonged pulmonary hypertension, leading to clinical signs of cyanosis, respiratory distress and eventually cardiovascular failure. 30,43 Thus, the prognosis is generally poor for horses with PDA that present with clinical signs.…”

“…1,8,16,30,43,44 PDAs are also more often reported in Arabian foals when compared with other breeds. 5,6,9,16,30 While reasons for the potentially increased prevalence of PDA in the Arabian breed have not been investigated, there are some predisposing environmental factors. For example, foals with dams that were given prostaglandin inhibitors may have an increased risk of developing PDA, as the ductus arteriosus normally constricts in response to inhibition of prostaglandin.…”

“…The atrial septal defect (ASD) and patent foramen ovale (PFO) represent defects causing inter-atrial communication that are often difficult to differentiate between. 8,9 As such, ASDs and PFOs are often included together in epidemiological studies, with the combined prevalence of these defects estimated to be 15%-44% of CHD equine cases. 7,8 However, it is likely that many small ASDs remain undetected in foals, as they produce little to no clinical signs and are unlikely to produce a heart murmur.…”

Postmortem magnetic resonance imaging findings of tricuspid atresia with ventricular and atrial septal defects and subvalvular pulmonic stenosis in a Japanese native Noma horse

“…Tricuspid atresia, the congenital absence of the tricuspid valve, has been sporadically reported in horses, mostly in Arab or Arab-bred foals [ 2 , 4 , 7 , 8 , 9 , 10 , 12 , 16 , 20 , 21 ]. The etiology of tricuspid atresia is likely multifactorial, involving environmental and genetic factors; however, no specific risk factors have been identified in humans or animals [ 18 ].…”