I've had runs of PVCs all my life (now 81) and had ablations for these and for tachycardia episodes a few years ago. These seemed to almost eliminate these unpleasant episodes. Before the ablations, I had been tried on Flecainide which didn't work for me.
On starting with predisolone for PMR, 3 months back I noticed some recurrence of PVCs at times. Tiredness, stress, indigestion, disturbance of vagus nerve tone? You notice them once you become sensitised to the feeling of being a bit 'off'.
Most people have the odd one and are unaware.
Another factor can low pulse rate and low blood pressure on starting steroids or adjusting dose.
If pulse is slow 50-60 bpm, the odd ectopic beat (PVC) becomes more noticeable. One cardiologist told me he also gets them and walks / runs up the stairs to raise his pulse rate..