It started with a sensation of tiredness, and my head was sweating abundantly.
I immediately put the pulse oxymeter, and took a nitro under my tongue.
Pulse went as low as 44 beats, and after few minutes it became regular, not random.
Then I managed to match breathing with my heart, and suddenly it came back with 108 beats.
Now to rest until dizziness disappear.
BTW it was painless.