Dear
Welcome to HCM
We understand your concerns
I went through your details. Deep breathing exercises are supposed to improve your heart rhythm and lower your heart rate. This happens because your body is reaching a metabolic optimum state of relaxation. In relaxed state, with slow and rhythmic breathing, your heart will be able to systematically pump blood to every part of your body without struggling and without being stressed. This relaxation happens only when your body and mind are actually relaxed.
You need to relearn the whole methodology of your breathing exercise. First of all you should understand your stress and stressed heart and heart rate. Then you should understand what is apprehension, obsession and
anxiety. Learning about these will give you knowledge enough to be relaxed. In yogic exercises, the breathing technique is given fourth place after even nirvana. I suggest you to consult a good
psychologist / spiritual guru who will be able to teach you all these. You should learn these from an experienced guru. Otherwise you cannot succeed.
A piece of advise. Please don't worry about the
increased heart rate during the breathing exercise. It is happening because you are anxious and obsessed with it. Ignore it and Leave it as it is and learn to get relaxed.
If you require more of my help in this aspect, please use this URL. http://goo.gl/aYW2pR. Make sure that you include every minute detail possible.
Hope this answers your query. Further clarifications are welcome.
Good luck. Take care.