Well, I have a bad heart so the numbers are skewed. I drank like 5-6 cups and started feeling shitty. I've drank more and felt fine, but I wasn't well hydrated. Palpitations can feel like all sorts of sensations in the chest, usually I experience a strong pounding sensation in my chest and sometimes my throat. I can't really tell you what an arrythmia feels like beyond 'bad' because by the time I'm having one or several I don't have enough blood in my brain to really remember clearly.
Crazy. I always wondered if you'd like, definitely know you were having palpitations, or sometimes maybe just when your heart feels funny it could be a little thing. Thanks for the insight, but also sorry you have to deal with that (not infrequently it sounds). (But really this is great material here.)
I definitely know when I'm having an event of some kind, but my sensitivity to such things is pretty high. The part about the hospital that is funny is that new or young docs always want to add something to my diagnosis when I walk in dehydrated. I ask for a bag of gatorade and nausea medicine, they run a bunch of tests, freak out because my blood makes me look like I'm having a heart attack, call my cardiologist, give me a bag or two of gatorade and nausea medicine, I go home. This has been the pattern of my ER visits for the past several years with a single notable exception when I managed to develop instantaneous or 'flash' pulmonary edema.