Discovery was quite by accident. Brother went for a sleep study because he started sleep walking. That doctor heard something, and suggested he get an echocardiogram. When he found he had this and that there is a genetic component, all 4 of us siblings got tested, but only those two had it. They had been monitoring for several years, but coincidentally crossed the threshold for the procedure in the same year.
This might explain some family history of healthy men dying suddenly in their 60s. OTOH, several aunts and uncles have since been tested, and none have the condition.
I have gone back through my history of working at VO2 max my heart rate stays well with in achievable range even when I have to stop to recover my legs. As far as I can remember I have never reached a high heart rate. Anther thing I noticed before I knew of my BAV was the FTP I seemed to fail at much lower levels than what I could do during regular workouts and I would just ignore the result and hold my FTP the same or increase 5% depending on how I was doing.