About 6 months ago I began to have a rapid heart beat, and some irregular heart beats. I went to the Cardiologist , had an EKG and his exam. He changed one of my medications from Atenolol to Metoprolol . Instead of my heart rate being my normal (for MANY years) about 60 - 64 at rest, it runs in the 80s. At 81 years of age, and what seems to be low testosterone, is there a connection?