The left and right atria in the human heart are responsible for collecting blood that is returning to the heart from the lungs and peripheral system. When these atria become enlarged, the condition can have a variety of serious effects.
Once blood has collected in the right atrium, it is pushed through the tricuspid valve and into the right ventricle, where it is then pushed to the lungs. Once blood has collected in the left atrium, it is pushed through the mitral valve and into the left ventricle, where it is then sent to the body.
Right Atrial Enlargement
According to the British Medical Journal, right atrial enlargement can be caused by several conditions, such as a stiffening or insufficiency of the tricuspid valve, which allows blood to backflow into the right atrium. Other causes include chronic obstructive pulmonary disorder (COPD) or a pulmonary embolus that obstructs the pulmonary artery.
Left Atrial Enlargement
The British Medical Journal also explains that left atrial enlargement can be caused by several factors, including stenosis of the mitral valve, which allows blood to backflow into the left atrium. Other causes include hypertension, hypertrophic cardiomyopathy and stenosis of the aorta.
If the left or right atrium becomes enlarged, the heart must work significantly harder to pump a sufficient amount of blood with each heartbeat. This increased workload puts significant stress on the heart muscle.
If left untreated, enlargement of the right or left heart atria might eventually lead to a serious cardiovascular condition, such as a heart attack or congestive heart failure. Additionally, insufficient blood flow to the brain might result in a stroke.