I recently saw on abc news that a diagonal ear lobe crease is a sign of heart disease. What is your opinion of this?

Yes. It is called frank's sign.It is a diagonal ear lobe crease extending diagonally from the tragus across the lobule to rear edge of the auricle.It may indicate cardiovascular disease or diabetes.
Not necessarily. Ear lobe crease is often observed in people with heart condition but it is not a cause or effect . It's presence does not necessarily mean that one has a heart condition or will developed one.