5.5 Ventricular septal defect
5.5 Ventricular septal defect

A ventricular septal defect (VSD) is the most common congenital cardiac lesion in the horse. The defect is usually situated at the base of the interventricular septum in the membranous or semi-membranous portion, just below the aortic root. Normally the septum fuses with the endocardial cushion at this point early in fetal development. Occasionally, defects are found in the septum just below the base of the pulmonary valve. These are due to abnormal development of the bulbus cordis. Defects in the muscular portion of the septum have also been reported. VSDs can also be found as a component of more severe complex CHD such as tetralogy of Fallot, tricuspid atresia and endocardial cushion defects.

Related Topics

5.5.1 Haemodynamic effects

5.5.2 Clinical signs

5.5.3 Clinical diagnosis

5.5.4 Further diagnostic aids

5.5.5 Prognosis

5.5.6 Treatment