I had been taking 50MG of Toprol for approx 1 yr with no apparent...

I had been taking 50MG of Toprol for approx 1 yr with no apparent side effects. A few months ago, I went through a Cox-Maze open heart procedure when my dosage was doubled to 100MG to help reduce my elevated heart rate of 120-140 BPM. My heart rate continued to remain high and I had a very pronounced shortness of breath, went to the ER where I was found to have fluid around my heart/lungs. After being treated with diuretics and a couple additional medications, the heart rate continued to remain high so my dose of Toprol was doubled to 200 MG....since that time, I have noticed increased muscle weakness, fatigue, and have almost passed out several times. It is a very scary and insecure feeling not being able to go anywhere or do anything in fear of passing out.