It all depends on what the problem is as to what your options are. If you have a ruptured aortic aneurysm, you're in trouble. If you have ventricular fibrillation and they put the automatic defibrillator on you, you have a chance. If you're just having a hyperventilation spell, you'll survive whether anyone helps or not.

In general, the options at 40000 feet are not good if you have anything seriously wrong. But, they're not good if you're driving a car in rural Wyoming when it happens, either.