Enlarged heart. Animation showing a healthy heart becoming enlarged, a condition known as cardiomegaly. There are a variety of disorders that can cause cardiomegaly including hypertension or a weakening of the heart muscle (cardiomyopathy). It may also occur in response to strain on the heart such as in obesity. The gradual loss of heart function (heart failure) leads to breathlessness and exhaustion, even when at rest.HD master is flattened onto a black background, as seen in this preview. The original file has a transparent alpha channel and is available as the HD master of clip K003 3741.