Increased left atrial load can be understood as an increase in pressure in the left heart and can be categorized into increased left atrial preload and increased left atrial afterload.
1. Increased left atrial preload: Increased preload is usually due to conditions that can lead to an increase in blood volume. These conditions cause an increase in the volume load of the left atrium, and are usually seen in congenital heart disease with a right-to-left shunt, large amounts of fluids over a short period of time, and renal disease resulting in large amounts of water and sodium retention. Increased left atrial preload usually results in volume expansion of the left atrium.
2. Increased left atrial afterload: Increased afterload is commonly seen in hypertensive disorders and mitral stenosis. Because of the increased resistance to blood flow to the left ventricle, the left atrial muscle needs to expend more energy to pump blood into the left ventricle, i.e., increased left atrial afterload. Increased left atrial afterload usually leads to left atrial muscle hypertrophy.
There are other causes of increased left atrial load, and it is recommended that you seek medical attention for the cause of your discomfort, and then treat the cause of the problem.