Do you do cardiovascualr activity? TRy increasing the amount you due to at least 30 minutes 3 x a week and see after a few weeks if your heart rate is going down.
all steroids can cause the heart to hypertrophy. if your worried, cut out the sat. fats and hit the cardio at least 3-4x/wk.
when on my resting pulse rate is ~88bpm and im only 26. steroids are not the sole cause of this, one needs to take into account age, level of activity, familial history...etc.
cardio is a must if your resting pulse rate is a constant 100bpm.
60 to 100 is considered "normal." e.g. not an arythimia, of the type tachycardia in your case. When you remove the cause your hr should return to normal. In the mean time, no, a heart rate of 100 is not life threatening in any way especially when it's not for a prolonged period of time.
Thanks for the advice people. I posted this thread 2 days ago and no one replied to it until now.
My partner who is a doctor has been worried about my elevated pulse rate. But I don't want to own up to the reason for it. I've been cunningly deceptive in explaining my increased muscle gains lately.