Ventricular septal defect Overview: ACHD, congenital heart disease, septal heart problem, hole in heart, complications, heart failure, pulmonary hypertension, types of VSD

Ventricular Septal Defect - What it is

The left and right sided blood circulation are usually kept separate. In patients with VSD, blood from the left lower chamber flows through the hole into the right lower chamber due to a pressure difference.

Ventricular septal defect (VSD) is a congenital defect of the ventricular septum, the wall which separates the heart’s left and right lower chambers (ventricles). During the formation of the heart, at the early parts of pregnancy, the ventricular septum does not fully develop, resulting in a hole. Typically, the left side of the heart pumps oxygen-rich blood from the heart to the rest of the body while the right side of the heart pumps oxygen-poor blood to the lungs. In order to prevent mixing of oxygen-rich and –poor blood, they are completely separated by the ventricular septum. However, when there is a defect/hole between the ventricles, blood from the heart’s left lower chamber is forced through the defect into the right lower chamber because of higher pressure in the left lower chamber. Therefore, a portion of oxygen-rich blood is recirculated back into the lungs resulting in inefficiency and forcing the heart to work harder.

Possible complications of Ventricular Septal Defect (VSD)

Leaving VSD untreated can lead to further complications and the severity of these complications depend on the size of the defect. If the VSD is significant in size, it may lead to the following complications:

Enlarged heart: Due to the additional blood volume recirculation and increased workload of the heart.
Pulmonary hypertension: High blood pressure may build up in the lung arteries from the increased blood flow to the lung.
Heart failure: The heart has to work harder, resulting in a large amount of blood being pumped to the lungs. This can eventually lead to heart failure.
Abnormal heart rhythms/Arrhythmia: In some cases, VSD might lead to irregular heart rhythms.

Complications associated with smaller defects include:

Endocarditis: This heart infection is a possible complication of VSD though it is rare.
Aortic regurgitation: Leakage of blood through the aortic valve.
Double chamber right ventricle: Abnormal muscle growth in the right ventricle resulting in two separate right ventricular pressure compartments.

Ventricular Septal Defect (VSD) classification

There are various types of VSD and they are classified according to their location within the ventricular setum.

1) Outlet VSD

The hole is located in the “outlet” portion of the ventricular septum, below the aortic and pulmonary valves.

2) Inlet VSD

The hole is located just below the tricuspid valve in the right ventricle and mitral valve in the left ventricle. It could also be a part of an atrioventricular septal defect (AVSD).

3) Muscular/Trabecular VSD

The hole is located in the lower part of the ventricular wall and there is often more than one hole. This is seen in 20% of infants with VSD.

4) Perimembranous/Central VSD

This hole is in the upper section of the ventricular wall.