I highly recommend Dr. Prachak Siriprakorn, whom everyone affectionately calls "Dr. Siri." He was my cariologist in Northern Virginia (went to his office in Woodbridge; think he had another one nearer DC, too).
He is of Cambodian descent and when I first visited him, I had a bit of difficulty understanding him. But I soon learned that he is absolutely brilliant! He was the one who got right to the bottom of what was going on with my aortic valve and root and what I would have to have done. Monitored me very closely.
And he recommended Dr. Alan Speir so highly to be my surgeon that he said if I came to the hospital the day of surgery and found Dr. Speir had been called away for some reason, I should walk out and come back for the surgery another day -- which wasn't a knock on Dr. Speir's associates (he has very competent ones) but just an endorsement of his extraordinary skill doing the valve/root replacement I had to have done. Dr. Siri said the surgery can take upwards of 11 hours, but Dr. Speir does it in 5 because he is so expert at it. That of course cuts down time on the heart-lung machine.
We moved away more than 5 years ago, and I haven't checked to see if Dr. Siri is still in practice there, but if he is, I highly recommend him.
(In fact -- adding a PS here -- I wish I could find someone as good as Dr. Siri where I now live. Have to go back for an echo this Friday, and I so far have not gotten confidence that my current cardio and his staff can interpret it correctly.)
Another edit add; I found this link to Dr. Siri:
http://www.insiderpages.com/doctors/Prachak-T-Siriprakorn-MD-Woodbridge