Right Atrial Enlargement

The heart weighs around 200 - 400 gm and is about the size of a fist. It's primarily composed of 4 parts, known as chambers. The functioning of the human heart is related to the proper coordination between these 4 chambers. These four chambers are called left atrium and right atrium (lie in the upper part of the heart), and left ventricle and right ventricle (located in the lower part of the heart). Blood circulation between these 4 chambers takes place with the help of heart valves that transport blood from one chamber to another.

Now, after having a general idea about the 4 chambers of the heart, we are in a position to understand right atrial enlargement (RAE). It is a condition of the heart where there is an enlargement of the right atrium, due to some infection. This increase in size of the right atrium is nothing but a deviation from its normal size, and is referred to as right atrial enlargement. Fatigue, chest pain and breathing problems are some of the common symptoms of RAE.

Functioning of the Heart

The heart is an organ that provides fresh oxygenated blood to the different parts of the body. However, the heart also receives impure (deoxygenated) blood. Impure blood from the legs and upper body gets accumulated in the right atrium, which is then transferred to the right ventricle through the tricuspid valve. From the right ventricle, the blood moves through the pulmonary artery to the lungs, for purification. Once the lungs complete their designated task, fresh oxygenated blood is then transferred to the left atrium. The blood is then passed down to the left ventricle through the mitral valve. The blood then flows out of the left ventricle and is distributed throughout the body.

RAE Causes

Why does the size of the right atrium increase abnormally? When the size of the right atrium increases, it is a symptom of an underlying medical problem. People suffering from high blood pressure have a higher chance of suffering from this heart disease. Other reasons that could trigger enlargement in right atrium are given below:

Lung Disease: As lungs play a very important role for normal functioning of the heart, any lung disorder may cause this heart problem. Disorders such as bronchitis or chronic obstructive pulmonary disease (COPD), can cause high blood pressure in the pulmonary artery that collects blood from the right ventricle. High blood pressure may ultimately lead to RAE.

Tricuspid Stenosis: This is a problem associated with the heart valve in which the tricuspid valve is unable to perform its job properly. As we all know, the valve that is between two chambers located on the right side of the heart, is the tricuspid valve. This valve ensures normal circulation of de-oxygenated blood from the right atrium to the right ventricle. Tricuspid stenosis is a heart valve disease in which the opening of the tricuspid valve is partially blocked, thus decreasing the flow of blood between these 2 chambers. In order to restore normal blood flow, the right atrium has to send the blood with more force, so that it passes through the narrowed opening of the tricuspid value. In case the blood is not pushed forward with extra force, there is a high probability that the blood may start moving backwards and cause further complications. So, this extra workload on the right atrium, often manifests in the form of RAE.

Mitral Stenosis: As aforementioned, the mitral valve lies between the left atrium and the left ventricle. Thus, one can say that the mitral valve is involved in the management of proper blood flow between the atriums and the ventricles. Any issues with this valve such as narrowing of the mitral value can cause RAE. In most cases, tricuspid stenosis is followed by mitral stenosis that leads to this problem.

Pulmonary Embolism: The pulmonary artery connects the right ventricle to the lungs. Now, this artery transports impure blood to the lungs for purification. Pulmonary embolism interferes with free flow of blood between the heart and the lungs, as a blood clot is formed somewhere in the pulmonary artery. Thus the heart has to work harder to try to normalize the blood flow in the pulmonary artery. As a side effect of these extra efforts, the heart may show RAE.

Tricuspid Regurgitation: This condition is related with the malfunctioning of the tricuspid valve. It is observed that the tricuspid valve opens only when there is a need of transfer of blood from the right atrium to the right ventricle. When the right ventricle fills completely, the tricuspid valve must close immediately. If the valve does not close after the ventricle is full, the blood may start moving backwards (tricuspid regurgitation), towards the right atrium. This excessive pressure of blood flow reversal can cause RAE.

Mitral Regurgitation: Mitral regulates blood circulation between left atrium and left ventricle. If the mitral valve fails to close itself after the left ventricle is full, the blood may flow in the opposite direction i.e towards the left atrium. These disturbances in normal blood flow in the heart may lead to RAE.

Right Ventricular Hypertrophy (RVH): RVH refers to abnormal increase in the size of right ventricle. As aforementioned, pulmonary arteries allows blood to move from the right ventricle to the lungs. However, poor blood circulation from these arteries can put a lot of strain on the heart. To be precise, when the blood flow moving towards the lungs is below normal, the right ventricle is subjected to excessive stress. As a response to this undue strain, the right ventricle shows abnormal enlargement. It is observed that people with RVH also tend to develop RAE. High blood pressure in pulmonary arteries, traveling at high altitude and pulmonary valve stenosis are some of the factors that trigger development of RVH.

Congenital Heart Disease: This is an inborn abnormality in the heart's structure. The heart does not get properly developed during the 9 months of pregnancy. This defect interferes with the normal functioning of the heart. When we talk about the structure of the heart, we cannot forget to mention about the tricuspid valve, pulmonary valve and the mitral valve. All these valves form an integral part of the heart's structure. Any deformity in the structure of the heart can affect any one or all the valves and disturb the blood flow through the heart, eventually causing RAE.

RAE treatment focuses on correcting the underlying cause. Taking a 2D echocardiogram of the heart is a reliable way to detect enlargement of the right atrium. Regulating the blood pressure is the key to control heart problems. So doctors may prescribe medications to control high blood pressure. Diuretics may be used to stop the build up of blood in the mitral or tricuspid valve. Respiratory disorders like COPD are treated with appropriate medications like bronchodilators (inhalers) and antibiotics to reduce COPD symptoms.