What is the most common congenital cardiac anomaly in horses?

What is the most common congenital cardiac anomaly in horses?

• A. ASD
• B. VSD
• C. PDA
• D. Pulmonic stenosis

Answer: (B)

In horses, ventricular septal defect is the most frequently encountered congenital heart defect. It arises when the interventricular septum fails to form or fuse completely during development, most often involving the membranous portion near the structure of the heart that forms the septum between the ventricles. This creates a left-to-right shunt at the ventricular level. The clinical impact depends on defect size: small defects may be quiet and easy to miss, while larger ones cause volume overload of the left heart, leading to a louder pansystolic murmur and possible signs of heart failure in foals or young horses. Because this area of septation is particularly prone to developmental error, VSDs occur more commonly than other congenital lesions such as atrial septal defects, patent ductus arteriosus, or pulmonic stenosis in horses. If the defect is large, echocardiography will show the shunt and quantify its size, guiding prognosis and management; small defects may be incidental findings.

In horses, ventricular septal defect is the most frequently encountered congenital heart defect. It arises when the interventricular septum fails to form or fuse completely during development, most often involving the membranous portion near the structure of the heart that forms the septum between the ventricles. This creates a left-to-right shunt at the ventricular level. The clinical impact depends on defect size: small defects may be quiet and easy to miss, while larger ones cause volume overload of the left heart, leading to a louder pansystolic murmur and possible signs of heart failure in foals or young horses. Because this area of septation is particularly prone to developmental error, VSDs occur more commonly than other congenital lesions such as atrial septal defects, patent ductus arteriosus, or pulmonic stenosis in horses. If the defect is large, echocardiography will show the shunt and quantify its size, guiding prognosis and management; small defects may be incidental findings.