failure fails to succeed

There is a sign on the wall of the cardiac unit at Christ Hospital in Cincinnati that says. Heart Failure does not mean your heart is failing.

The sign goes on to explain that heart failure simply means that the heart isn't effective at doing its job. (my own words here)

The sign has me puzzled. Not about heart failure, about definitions. How do they define failure? Isn't a definition of failure not effectively succeeding?  Isn't failure not doing one's job?

Obviously, this is not complete and total failure -- it's okay to get help when help is needed. Sometimes, failure to ask for help is more of a personal prideful failure.

The sign is meant to reassure. I know that. But why lie? Heart failure means your heart is failing on its own. We are here to help, and there are things we can do that will help.

Don't say failure isn't failing. Because it is. Even then, some failures are successful. What would they think of that? How will they explain it?