Watch more How to Understand Heart Disease videos: http://www.howcast.com/videos/512532-What-Is-Heart-Failure-Heart-Disease So what is heart failure? Also known as congestive heart failure. Well at its very core, it is any condition in which the heart muscle function is not enough to keep up with the demand. What we really mean, however, when we talk about heart failure is a weakened heart muscle. And this can come from a lot of different causes. One cause may be a heart attack, which has weakened the entire heart or parts of the heart. A second cause may be conditions which directly attack the heart muscle. These can be a variety of different toxins that poison the heart muscle. Things like excessive alcohol or certain chemotherapy agents can directly attack the heart muscle’s function. A third class of causes of heart failure would be infection. Some viruses can do it, such as HIV and hepatitis, and other different types of infections can directly attack the heart muscle’s function. Some basic signs of heart failure would be effort intolerance, the ability to exert yourself. Another one would be frank shortness of breath, either at rest or, again, while you’re exerting yourself. And the third most common sign of heart failure would be edema, or swelling, of your legs. So if you’re having any of the signs or symptoms of heart failure, your doctor may want to do some basic tests, such as cardiac ultrasound, to see how your heart muscle function is working. Basically that is what heart failure, or congestive heart failure, is.