Comment by FrankWilhoit

I, too, have found that in the presence of a-fib, the optimal amount of caffeine is not zero; but I must think that every patient is different. Most people with diagnosed a-fib also take a beta blocker, and I (just only me) found that an excess of the beta blocker had paradoxical effects. So there is another potential interaction. Then, I also voted myself a small dose of OTC lithium, and subjectively derived obvious and substantial benefit from it, but there is (as yet) no science behind that, so I will not assert causation.