The heart develops from a large tube, dividing into sections that will eventually become the walls and chambers. Ventricular septal defects happen during fetal heart development and are present at birth. VSDs can be located in different places on the septum and can vary in size. The heart murmur can be heard when a doctor listens to the heart with a stethoscope.

The blood flowing through the hole creates an extra noise, which is known as a heart murmur.

In the right ventricle, this oxygen-rich blood mixes with the oxygen-poor blood and goes back to the lungs.

When the heart beats, some of the blood in the left ventricle (which has been enriched by oxygen from the lungs) flows through the hole in the septum into the right ventricle.

People with a VSD have an opening in this wall. The right and left ventricles of the heart are separated by shared wall, called the ventricular septum. What Happens in a Ventricular Septal Defect? This means that the chances are good a VSD is no longer causing problems for a teen. It's pretty rare for a VSD to go unnoticed until the teenage years.

Ventricular septal defects (pronounced: ven-TRIK-yu-lar SEP-tul DEE-fekts) are the most common congenital heart defect, and in most cases they're diagnosed and treated successfully with few or no complications. In a VSD, there is an abnormal opening in the wall between the main pumping chambers of the heart (the ventricles). A ventricular septal defect (VSD) - sometimes referred to as a hole in the heart - is a type of heart defect.

Blood on the wall