First off, since the conclusion is "normal" and "don't need to see the cardiologist again", no need to worry yourself sick.
That said, a few points.
1) Phen/Fen is known to cause heart damage, and Lisa/fr1endly2 was in a class action suit for this. The mild regurgitation could be a result from this. I take it the cardiologist knows this history, so this is taken into account with the overall diagnosis. If not, let him/her know, and see what is said about that.
2) Being overweigt for a long time, plus high blood pressure can put a strain on your heart and cause the regurgitation and thickening of the heart muscles.
3) True, thyroids sometimes cause heart issues, too.
The point though is, that what you have are all within normal limits. Since it's been reported, I'd say on the high end of normal, but still, not at a level where a regular follow up or treatment is necessary. Also, the factors that will make the issues progress have been removed--except aging
.
I will admit, as you age--age in itself is a deteriorating factor for much of our functions, the easiest thing for us to work on improving with age is our wisdom and maturity
--the level of damage MAY progress. If you are worried, have a check that includes echocardiogram and stress ECG every 3-5 years in your age bracket, and probably every year or 2 above 60 IF the regurgitation and thickness (hypertrophy in medical terms) increases. In between, annual ECG is recommended, but then this is recommended for any/everyone even if things are normal. If no change with the regurgitation and hypertrophy, then probably every 2-3 above age 60 is good enough.
Heart Help...Doc?
KB
So long as you are putting your best foot forward, then, 
Linear Mode
