I’m prone to low blood pressure, heartbeat’s slow too. When you’re on the verge of fainting, getting down low, or prone, ASAP, both helps and can prevent injury from toppling. A specialist said I’d likely need a pacemaker in about a decade. That was about 10 years back. I’d much rather not.
I'm not sure how much time you can count on—how long consciousness and voluntary motion persist—if the heart in fact stops. I think I read somewhere (not sure where, at the moment) that a person in ventricular fibrillation is inevitably unconscious, more or less immediately. It may be that the sensation of stoppage you've felt is something short of actual stoppage, so far anyway. I've heard of people having sleep apnea, whose breathing stops for a spell while asleep, and SpO₂ drops, sometimes triggering changes in heart rhythm. I think I would want an explanation for why SpO₂ was dropping like that while awake and alert. Could that suggest that something about breathing, or oxygen transfer in the lungs, isn't happening efficiently? Maybe the diagnosis of HF earlier is part of that story. I don't even play a physician on TV. This may be worth getting an opinion from someone who knows the stuff.
