What is the definition of the heart condition of cardiomyopathy?

Cardiomyopathy is defined as a disease of the heart muscle that affects its size, shape, and ability to pump blood. The correct answer emphasizes both the enlargement and stiffening of the heart, which can lead to several complications, including heart failure. In this condition, changes in the heart muscle can hinder its efficiency, resulting in symptoms such as shortness of breath, fatigue, and swelling in the legs and ankles.

The options that describe thickening of the heart wall relates more specifically to hypertrophic cardiomyopathy, a type of cardiomyopathy, but it does not encompass the broader definition. Irregular heartbeat refers to arrhythmia, which can occur due to various heart issues but is not specific to cardiomyopathy. Lastly, weakness in the heart valve pertains to valvular heart disease, which is distinct from the muscle abnormalities characterized by cardiomyopathy. Thus, the definition of cardiomyopathy is best captured by the description of both enlargement and stiffening of the heart.