Tachycardia only when trying to nap

[Mamalilbird]

Hello all, so i have a laundry list of chronic illnesses from autoimmune diseases to cerebrovascular to subclincincal hyperthyroidism whatever it is i probably have it. Just bad genetics. So i have a short pr interval, mitral valve prolapse and tricuspid regurgitation,  and palpitations with my heart i am waiting to get into a new cardio but until then i am freaking out. For over 2 years and no answer- i have been waking up to tachycardia and feeling smothered. It only happens if i am half alseep or i wake up from it. I can lay down like that for hours and nothing happens. It only happens while half asleep or asleep.  It happens mainly when i am trying to take a nap. This is daily for years. Its to thr point where i am afraid  to sleep. Does anyone have any insight on this?