what causes muscles to enlarge
High blood pressure can cause the left ventricle to enlarge, causing the heart muscle eventually to weaken. High blood pressure may also enlarge the upper chambers of your heart (atria). 1  Heart valve disease.
Quick Answer. Though there are a number of conditions, both congenital and acquired, which cause left atrial enlargement (LAE), a study by the American College of Cardiology found that the two most statistically significant causes are obesity and high blood pressure.