I feel your pain my brother. I get them out of no where also. I can be sitting watching tv and bam I feel it then my minds racing along with my heart. I quickly grab a Xanax drop it under my tongue and wait while I pace and splash water on my face. After it’s over it makes me so angry because I have no control and never will. You can be the baddest mfkr on th planet but get hit with an attack and your nothing!