Hello,
Thank you for asking your query.
From your description I understand that your sister has been recently found to have a slight murmer, caused by a leaky mitral valve. This probably is a condition called mitral regurgitation. And there is nothing to be overly worried about it !
The reason being, a leaky mitral valve is a common occurance. Infact A trivial amount of MR (mitral regurgitation) is detectable with sensitive Doppler techniques in up to 70 percent of healthy adults; this is often termed "physiologic" mitral regurgitation. Another study called Strong Heart Study showed moderate valve leak was found in 2 out of 100 normal people. The fact that she is does not have any kind of symptoms is a very positive sign. She has excellent Lipid profile, stays active and healthy. So I have the same thing to say as her Doctor said not to worry.
The previous Doctor might have over looked it. This happens occasionally because of the above said reasons (common, not very harmful etc). Your Doctor has recommended the right thing for your. An yearly Echo and physical examination is the best way to monitor the progression , to be safe. Other than that there is no need for any other active intervention.
Wishing you the very best and Good health
Dr.Deepak Misra MD, DM
Fellow in Interventional Cardiolgy
www.doctorspring.com