Nonischemic cardiomyopathy is damage to the myocardium (heart muscle) which is not associated with interruption to the heart's blood supply. In ischemic cardiomyopathy, the heart muscle is damaged because there is a restriction or interruption of oxygen-rich blood supply to the heart caused by blockage or narrowing of blood vessels, while in nonischemic cases, the patient has another medical condition which leads to injuries to the myocardium. Over time, the damage puts strain on the heart and exposes the patient to the rest of complications like heart failure.
Nonischemic cardiomyopathy includes several types, but the three main types are dilated, hypertrophic, and restrictive cardiomyopathy. The name of each describes the nature of its muscle damage. The most common form of nonischemic cardiomyopathy is dilated cardiomyopathy, where the largest chamber in the heart (the left ventricle) becomes enlarged, causing the heart to pump less efficiently. The heart has to work harder to circulate the blood, putting significant strain on the heart muscle. The patient may struggle while exercising and when under stress, and can develop difficulty breathing and physical weakness because the heart is not working right.