Good Morning, I am a 44 year old female, 156 pounds. being treated for conjestive heart failure, dilated cardiomyopathy, and arythmias possibly caused by a virus. It has been two years now of treatment and three ablation proceedures and am starting to feel a lot better and have been given the go ahead to get the heart working again with exercise, which is great because I have always been a very active person. Still sluggish though because of the meds. My question is....my heart rate gets up to 170-175 beats per minute during my workout, is this safe?