AF? Severe c.a.c?

[lynisa48]

hi after a chest X-ray they reported calcification of coronary arteries I’ve seen consultant who is saying c.a.c is severe had echo ecg blood tests myocardial perfusion scinitigraphy scan all came back normal then last Sunday woke up to my heart racing at 158 beats per minute after about an hour went back to normal, visited A&E had more tests they couldn’t find the cause but when I pressed for an answer they said likely AF

after all that my question is having the all clear is the high heart rate more likely to be AF or brought on by anxiety also how likely is c.a.c to be severe if test normal feeling confused