I was put on it for palpation and my heart rate would drop down to the low 40's. My cardiologist told me as long as your not dizzy or short of breath. Well it made me dizzy and short of breath. I went to the ER for a UTI and the Doctor that I saw told me to stop taking it. He said your heart rate is usually normal and if this stuff takes it to low there's no coming back. I have not taken it since. Turns out I was having the palpitations due to having a little pneumonia in my lungs and it went to long without being diagnosed that I also developed something called pneumonitis. Pneumonitis is pretty scary. I looked it up. I did 7 days of antibiotics for the pneumonia and was still having g shortness off breath but my oxygen registered normal. Finally got a CT Scan instead of a x ray. I am praying my lungs don't have permanent damage now from going so long without being diagnosed. I can't seem to find go Doctor's anymore and the specialist I had been referred to have not helped either huh