I began taking Atenolol/Tenormin for about 3 months now for Mitral Valve Prolapse. At first I believed it was working at indeed felt a lot better. Up until about 2 to 3 weeks ago I have experienced SWOLLEN ANKLES, SHORTNESS OF BREATH, EXTREME TIREDNESS, SORE MUSCLES, LACK OF ENTHUSIASM. If you are currently taking this, stop now. It is just a downward spiral. I recommend daily walking, healthy diet, and lots of water. My mother did this when she was diagnosed and stopped taking the drugs and it worked wonders.