I was diangosed with syncope on standing shortly after getting Covid (the
first time).
I'd never experienced anything like this before in my life, but suddenly the world would fade to black if I stood up too soon from a reclined position. I also experienced intense brain fog. I actually scheduled a doctors appointment specifically for "brain fog" at the time and they were confused as to what I was explaining. All I could say is that it felt like I was thinking through "mud" and lost my ability to focus. I wasn't even thinking of Covid when I booked that appointment, but looking back it makes sense.
This has gotten better with time, but I have no doubt that Covid had something to do with this. The timing was just far too coincidental. The fact that it has strong binding affinity to ACE-2, which can cause cardiovascular issues, only lends credence to this theory.