Not suprising. I'm no doctor, they know best when it comes to this stuff but I'll take a few guesses.
PVC's cause an extremely short period in which your blood pressure falls.
This fall in blood pressure is enough to activate the sympathetic nervous system (release some adrenaline), this in turn causes your heart rate to briefly increase.
This gives us 2 mechanisms that could potentially cause that hot feeling from the PVC alone.
Start adding psychological factors such as fear or anxiety caused by the sensation of the skipped beat and what you get is a whole slew of neurotransmitters, hormones and corticoids in the mix, any of which could be the culprit as well.