Cardiomegaly and cardiomyopathy both affect the heart muscle. Cardiomyopathy is a disease in which the heart is inflamed and its functionality is reduced. The Mayo Clinic reports that cardiomegaly or enlarged heart, while it does have symptoms, is not a disease but considered a byproduct of another condition.
Cardiomyopathy may have no clear cause (ideopathic) or may be due to several causes including high blood pressure, heart valve diseases and congential heart defects, according to the Amerian Heart Association.
The Mayo Clinic reports that cardiomegaly may be caused by, among other things, cardiomyopathy, high blood pressure, thyroid conditions, and protein buildups in heart.
Cardiomyopathy has three types (dilated, hypertrophic and restrictive), according to the American Heart Association. Cardiomegaly is not divided into types.
Cardiomyopathy and cardiomegaly have similar symptoms and can include dizziness, swelling of the lower limbs, shortness of breath and arrhythmia.
Both cardiomyopathy and cardiomegaly are treated by addressing the underlying causes. Treatment methods can include medications (such as beta blockers) and surgeries to correct blockages or repair defects.