I am a 58 years old male. i had a bypass surgery and a mitral valve replacement in feb'12. since a few days, i am noticing a very slight breathlessness. why?

Mitral valve / chf: Please see your cardiologist. / pcp and get it checked out . Differential diagnosis would include mitral valve problem , heart muscle weakness, deconditioning , lung problem. After examination consider getting 2d echo to determine state of your heart valve and ejection fraction and also chest x-ray and routine CBC and cmp at the least. Make appt with your md.

Many possibilities: It could be as simple as a cold, or you may be in heart failure - or many things in between. You should see your cardiologist to follow up an address this problem. The internet is not the best place to get answers - always remember to talk to your doctor.

Concerned: I agree with the first answer. The possibilities are broad but many of the possibilities are easy to address if you address them quickly. Even a simple infection can become a big issue when you have heart disease and a valve replacement if you don't address it.