I consider myself NT. I can detect my heartbeat in my eyes, my hands, my forehead and my belly. As you say, I normally filter it out.
(I'm a bit of a mutant: I have a strong pulse in the crook between thumb and forefinger on each hand. For decades, I wondered why nurses checked patients' pulses on their wrists when the one in the hands is so much stronger. Apparently no one else has it -- that's why!)