I heard this before from my mother and she's a nurse too.
My grandfather had a crease in his ear, he had 4 heart attacks and bypass. Survived all 4.
I see I have a crease in my ear now too, not sure if i'd have a heart attacks but sometimes I do get chest pains.
Not sure if that is heart related but it's in that area.
I'd like to know if it's a proof positive theory. If not, it's fun anyway.