Dr. Mersch received his Bachelor of Arts degree from the University of California, San Diego, and prior to entering the University Of Southern California School Of Medicine, was a graduate student (attaining PhD candidate status) in Experimental Pathology at USC. He attended internship and residency at Children's Hospital Los Angeles.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
A ventricular septal defect (VSD) is a heart malformation present at birth. Any condition that is present at birth can also be termed a "congenital" condition. A VSD, therefore, is a type of congenital heart disease (CHD). The heart with a VSD has a hole in the wall (the septum) between its two lower chambers (the ventricles).
How common is a VSD?
The most frequent types of congenital malformations affect the heart. It is estimated that approximately
eight in 1,000 newborns have CHD. A VSD is the most frequent of the various types of CHD (25%-30% of all CHD). Approximately one infant in 500 will be born with a VSD.
What is the normal design of the heart?
The heart is made up of four separate chambers. The upper right chamber (atrium) receives blood back from the body with much of the oxygen extracted by the body organs and tissues. The blood is then pumped through a one-way valve into the lower right chamber (ventricle) from which it is pumped to the lungs to be again enriched with oxygen. This highly oxygenated blood then returns to the upper left sided chamber (atrium) and next passes through a one way valve into the lower left chamber (ventricle). From there, the oxygenated blood is pumped out into a large blood vessel (the aorta) and is distributed throughout the body through arteries.
The two upper chambers (right and left atria) are separated by a wall of muscle called the septum. Similarly the two lower chambers (right and left ventricles) are also separated by a separate muscular septum. These septa (plural of septum) keep the lower oxygenated blood that has returned from the body from mixing with the highly oxygenated blood which has returned from the lungs.