A Ventricular Septal Defect (VSD) is an abnormal communication between two of the chambers of the heart. The pressure in the right side of the heart is generally lower than the pressure in the left side. This causes the blood to flow from the left heart to the right. In a healthy heart, the blood flows from the right side of the heart through the lungs to the left side of the heart. If there is a VSD present, the abnormal flow will circulate back through the lungs again. This increased flow through the lungs can cause signs of congestive heart failure.
Symptoms include fluid in the lungs and difficulty breathing. The murmur heard on your pet is caused by the abnormal jet of blood flowing through this hole. The treatment as well as the long term outlook for your pet will depend upon the size of the hole and the amount of shunting that occurs from the defect.