Because I'm very thin and have a minor case of pectus excavatum, I tend to feel the palpitations quite distinctly, though especially while inactive and sitting or laying down.
I have good days, sometimes stretches of days, in
which I feel almost none. Then, without any discernible change in my behavior, I have bad days that may include periods of time with 3 to 4 PACs/min. I've had EKGs, a chest x-ray, cardiac MRI with and without contrast, and an echo.