Hello and thank you for asking HCM, I understand your concern. Trace mitral regurgitation means mild, so actually in this stage you are in the compensated phase, which means that you shouldn t have any symptoms. Breathing symptoms occur in any progression of mitral regurgitation. So if your brathing problems haven t progressed lately, these symptoms are probably connected with asthma. My suggestion is to follow your symptoms, for example the length that you can walk across without problems, the number of floors on which you can climb, or when you get problems while sleeping horizontally. If you manage any changes visit your doctor as soon as possible to clear if the cause are your heart problems or asthma. I hope this answer was helpful to you.