Three weeks ago I did cocaine and drank alcohol, the next morning I had a panic attack and thought I was having a heart attack. I felt like i was being stabbed in the heart. Since then I have been getting palpitations when i do minimal physical exercise (170 bpm while power walking), tightness in chest (occasional pain), and headaches. I have seen a specialist and my results have all come back good. I get my 24 hour ecg results this tuesday, and may be pescribed beta blockers. However, my heart rate at night when im resting is 55 bpm. Would it be safe for me to take beta blockers? Also will these symptoms ever go away? I'm 23 years old, and fairly fit, should I be concerned? I Have taken drugs such as MDMA, LSD, cannabis etc in the past.