Hi Steve good the hear from you!
Is your friend having any shortness of breath either with exertion or during cool down rest period after exercise?
If so, it's good firhim to get a work up and check fir possible PV stenosis. It is relatively uncommon these days, but not too rare as we would like to see. eses
His pulmonologist is a good place to start. The key to effective treatment of a possible PV stenosis is early diagnosis, so if it turned out to be PV stenosis caused pulmonary HT, then not finding out fir 4 years after the ablation could make it hard to do much about it. Anyway , it's likely from another source other than stenosis. Also let's take it a step at a time and not speculate too far ahead.
Keep me posted!
Shannon