Perhaps I skimmed over it a little quickly, but has anything been detected recently? I had a murmur detected by a doctor during my first class 1 renewal, by which time I was significantly into my flying course and significantly in debt. As with one of the earlier posters, I had an echocardiogram, an extra ECG and a coupe of other tests, all of which showed me to be in good health.
It hasn't been detected in any subsequent medicals, though for a few years after the detection I carried the reports clearing me of any problems to subsequent examinations, as I had to have another intial for a foreign license.
Anyway, if it hasn't reared its head recently or you have been cleared previously I would guess you will be ok, that was my experience at least. Good luck!