The heart is composed of four chambers. The right and left atria are smaller chambers on top of the heart. The right and left ventricles are larger chambers underneath the ventricles. The atria pump blood into the ventricles. The right ventricle pumps blood to the lungs at the same time the left ventricle is pumping blood to the rest of the body.
Congenital Abnormalities
The heart undergoes a series of complicated arrangements during development. Problems at any stage can damage one or both ventricles. For example, a ventricular septal defect is a congenital abnormality of the ventricles in which the wall separating the right and left ventricles has a hole in it. In normal circulation, the blood will flow from left to right through this hole. The increased blood through the right side of the heart and lungs can cause high blood pressure in the lungs. Another example is hypoplastic left heart syndrome. In this syndrome, the left side of the heart, including the valves and the ventricle fail to develop properly.
Cardiomyopathies
Cardiomyopathies are diseases involving deterioration of the heart muscle. The most common form is dilated cardiomyopathy, according to "Robbins and Cotran Pathologic Basis of Disease." In this form, the ventricles, especially the left, dilate and cannot pump effectively. It may be hereditary or acquired; alcohol is one known cause. Hypertrophic cardiomyopathy is hereditary. The ventricles thicken and obstruct the flow of blood. A third type of cardiomyopathy is restrictive. In this type, the ventricles become thick and do not fill with blood.
Scarring and Fibrosis
The heart can also be damaged and the ventricles may develop scar tissue as a result. In a heart attack or myocardial infarction, blood is cut off from being delivered to part of the heart. It is common for the left anterior descending artery to be deprived of blood, according to "Hurst's The Heart." The part of the heart muscle that was supplied by the artery can no longer pump blood. The muscle then turns into scar tissue, and may even bulge out, forming an aneurysm. Heart failure can ensue.
References
- "Robbins & Cotran Pathologic Basis of Disease"; Vinay Kumar et al; 8th Ed 2009
- "Hurst's the Heart"; Valentin Fuster, Robert O'Rourke, Richard Walsh, and Philip Poole-Wilson; 12th Ed 2007
