clogged arteries around the heart .... given his weight, diet, inactivity, that would be a decent guess. Now being POTUS, I'm sure he's being jabbed with all type of anti-coagulants and such to keep him from keeling over. But the lividity bruising around his hands is another bad sign. If he completes 3 more years without dropping dead, becoming a babbling mess or having a massive stroke and become a vegetable, I for one will be impressed by modern medicine.
Hoping for such would then put J.D. eye-liner (Vivian) Vance in charge, with dead-eyed christo-fascist freak Johnson waiting in the wings. God help us all!