Causes

Left ventricular hypertrophy has several causes — one is an increase in the size of heart muscle cells and the other is abnormal tissue around the heart muscle cells.

Your heart muscle cells may get larger in response to some factor that causes the left ventricle to work harder, such as high blood pressure or a heart condition. As the left ventricle's workload increases, the muscle tissue in the chamber wall thickens. Sometimes, the size of the chamber itself also increases.

Left ventricular hypertrophy may also develop due to problems in the structure of the heart muscle cell. These changes can be related to a genetic defect. Abnormal tissue around the heart muscle cells is a result of several rare conditions.

Factors that can cause your heart to work harder include:

• High blood pressure (hypertension). This is the most common cause of left ventricular hypertrophy. More than one-third of people show evidence of left ventricular hypertrophy at the time of their diagnosis with hypertension.
• Aortic valve stenosis. This disease is a narrowing of the aortic valve that separates the left ventricle from the large blood vessel leaving your heart (aorta). The narrowing of the aortic valve requires the left ventricle to work harder to pump blood into the aorta.
• Athletic training. Intense, prolonged endurance and strength training can cause the heart to adapt to handle the extra workload. It's unclear whether this athletic type of left ventricle hypertrophy can lead to stiffening of the heart muscle and disease.

Abnormalities in heart muscle cell structure that result in increased heart wall thickness include:

• Hypertrophic cardiomyopathy. This genetic disease occurs when the heart muscle becomes abnormally thick, even with completely normal blood pressure, making it harder for the heart to pump blood.
• Amyloidosis. A condition that causes abnormal protein deposits around the organs, including the heart.