Elevated Vital Signs 3-4 Mo after AVR (Bypass)

I, too, have had breathing difficulty since Aortic valve replacement (bypass machine) on March 10, 2008, almost 4 months.  My blood pressure and heart rate, which have always been very good (systolic between 105-115) are elevated (systolic won't reliably go below 130-150) and have not normalized.  I have a cough since a couple of days after surgery--initially a dry cough, but by now the bronchial passages are irritated and it is somewhat productive.  The coughing is pretty constant.  I am not congested nor do I suffer allergies.  My resting heart rate was dropping soon after surgery, but for a couple months now it’s hung up and won't go below 185-195 without a beta blocker and 178-190 with Atenolol.  My total cholesterol level before surgery was 171, and now it is 207.

Other post-surgical symptoms which have been resolved satisfactorily are aenemia (37.5) and a low-grade fever during the first couple of months.  About once a month, I have stabbing pains in my left shoulder (other discomfort as well) which I have learned to associate with noninfectious pericarditis.  I treat it for several days with ibuprofen, until a day or two after the chest and shoulder pain cease.

I work a great deal at diaphragm/abdominal breathing.  If I don't, I feel that I am not able to get air into my lungs.  I had never seen my O2 saturation below 98% before surgery, but now it may be anywhere in the 90s (usually 93-94 up to 98).  Using the inspirometer, I have no difficult inhaling 2000 ml.

My questions for now, of course, are:  Which of these numbers should have normalized by now?  What are the possible etiologies of these persistent changes?  Which if any of these changes (especially breathing!) are, at this point, likely to be permanent?  How is paralyzed diaphragm diagnosed?  I have read that if this condition exists, not only is it going to continue making my life miserable, but it may greatly increase the risk of mortality if/when I need reoperation; is this correct?

Thanks very much.