In general, when an aortic valve is stenosed, the heart needs to work harder to pump blood through the valve to the body.
As long as the stenosis is not severe, and in your case you are far from that with "only" mild stenosis, there are seldom real problems.
Also regurgitation will not have a noticeable effect on the ventricle as long as it is not moderate or severe.
It is very improbable that the LV would become enlarged from mild AS and/or trace AR.
The reference range for LV is 4,2-5,9cm for men, so there is no enlargement and you are within the normal range. The fact that you are in the upper part of the reference range can indeed be from the fact that you are tall.
The fact that the aortic valve is bicuspid makes monitoring necessary.
At present, I really do not see any reason for worry.
If you have no symptoms at age 26, which is still pretty young, and are in otherwise good health (good control of weight, BP, etc), you probably have quite a few years to go before worrying.
However, roughly 80% of people with bicuspid aortic valves will require valve repair or replacement later in life, often in the late 40s or early 50s (this was the case with Arnold Schwartzenegger). Almost inevitably, the edges of the valves thicken and stiffen with time, which causes the heart to work harder, thereby increasing LV size and wall thickness.
Everyone with a bicuspid valve should be under the lifelong care of a cardiologist, and should receive regular checkups of the heart's size and condition, so that any serious decline in the valve's function can be detected early, and any needed surgery can be done in a timely way.
You should be reassured that this type of surgery is fairly common now, extremely sophisticated, and generally very, very safe and successful. And who knows, you might be among those who develop no problems. But it is wise to keep an eye on things.
Enjoy your life, and live it wisely, with the knowledge that if you should run into trouble, there is excellent help for you.
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