What is Atrial Hypertrophy?

Atrial hypertrophy is a medical condition in which the right atrium of the heart becomes enlarged because of thickening of the heart walls and an increase in the overall size of the atrium. The enlargement causes changes in the normal electric impulses within the heart. When this happens, the heart begins to beat improperly.

A normal heart beat has four parts. They follow each other in rapid succession as blood pumps through the four chambers of the heart. In a person who has atrial hypertrophy, the right atrium pushes blood through to the right ventricle in a way that is out of sync with the rest of the heart.

On an electrocardiogram (ECG or EKG), which measures the electrical impulses within the heart, the waves of the right atrium and those of the left atrium should be almost identical, except that the right waves start first. When right atrial hypertrophy is present, the right wave is often much larger than the left and overlaps the left. This means the right atrium is pushing blood through the tricuspid valve and into the right ventricle before the ventricle is ready to receive it. The result of this is an eventual lack of oxygenated blood being pumped back into the bloodstream.

The right atrium is considered by most doctors to be out of normal size range when it is measured by ultrasound to be more than 1.5 inches (4 centimeters) in diameter. This is also called atrial dilation. If the atrial enlargement remains undiagnosed, other parts of the heart can suffer damage. They may become weakened or, in the case of ventricular hypertrophy, enlarged.

This can happen for a variety of reasons. Hypertrophy is often a reaction to high blood pressure caused by stress and other health issues. Usually the enlargement of the atrium is a result of an underlying medical cause. Some of these causes include genetic diseases, including metabolic storage diseases; altitude sickness; chronic obstructive pulmonary disease (COPD); chronic bronchitis; and emphysema. A history of smoking is also common among sufferers.

There is no direct cure for this type of enlargement of the heart. Neither medication nor surgery has shown any prolonged improvement for atrial hypertrophy. Cardiologists agree that the best way to treat this problem is to find and treat the underlying cause. If the damage that has already been done to the atrium is reversible, it will decrease in size on its own as the underlying condition is resolved.