anxiety s.v.t. sleeping

I wake up around 4 am with a very rapid heartbeat of 160 - BUT the beat isnt normal - it jumps a;; over- very irregular (hit as high as 200 or more) that last 60 -90 minutes - I have dry mouth  and I feel anxious or scared - I try to breath but my throat feels dry.  The heart beat will stay in the 130-190 range most of the period and occasionally I'll feel it slow and then race up - once I sit -either on the floor and put my head on the bed or in a chair and head on the table, I try to focus and fall asleep - I'll hear some abrupt sound and feel a slight pain in or around my collar bone -sometimes none at all and then the normal beat or sinus returns - its gone just as fast as it came. WHAT IS THIS? panic SVT or something MVP?? combination?