A ventricle is a small cavity or chamber that may be found anywhere in the body, but has become associated primarily with the brain or heart. Due to their different locations, enlarged ventricles may result from a variety of factors, or they may occur without being triggered by an obvious cause.
The brain has four ventricles that produce, and are filled with, cerebrospinal fluid. The fluid flows through the ventricles and into the spinal canal, where it forms a cushion that protects the brain and spine. The heart has two upper and two lower chambers. The lower chambers are called the right and left ventricles. The top right chamber of the heart receives deoxygenated blood from the body and sends it down to the right ventricle, which pumps the blood to the lungs to receive oxygen. That oxygenated blood then flows back into the top left side of the heart, then goes down to the left ventricle, which pumps oxygenated blood through the aorta into the body.
Left Heart Ventricle
When the left ventricle doesn't pump blood efficiently, the muscles stretch and cause the ventricle to become enlarged. This condition, called congestive, or dilated, cardiomyopathy, may occur without an obvious reason. According to the Mayo Clinic, other causes of congestive cardiomyopathy include genetics, an infection and cardiovascular disease. The mitral valve controls the flow of blood between the left upper and lower chambers. In a mitral valve prolapse, the valve has extra tissue that prevents it from closing properly, and this may cause the left ventricle to enlarge as extra blood seeps through the valve into the ventricle.
Right Heart Ventricle
Pulmonary hypertension is high blood pressure in the vessels that carry blood from the heart to the lungs. As the pulmonary vessels become blocked or damaged, the heart must work harder to push blood out to the lungs. This pressure may cause the right ventricle to become enlarged. According to familydoctor.org, pulmonary hypertension may appear on its own or may be caused by congestive heart failure, birth defects, blood clots, liver disease, lung disease or some medications.
When excess cerebrospinal fluid accumulates in the ventricles of the brain, they enlarge and the resulting condition is called hydrocephalus. The Hydrocephalus Association notes that when it is present at birth, it's often caused by genetics and is called congenital hydrocephalus. However, hydrocephalus can occur in anyone at any age as a result of a stroke, infection, tumours or a brain injury. Fluid in the enlarged ventricles puts pressure on the brain that may cause permanent damage or death.