Pressure Spike while resting

Where does this come from? Consider this, I am sitting down at the computer and then I feel a surge and my ears go "heavy" and I am scared of what I do not know. Sometimes I have a taste on my tongue or feeling of dryiness in my mouth/lips. How much of this is heart? I have don the tests and pheocromacytoma has been dicounted. I have an ICD from cardiac arrest last year. It has fired a few times sometimes unexpectedly too. Interrogation says There was a rythm issue and therapy was needed to stop the "progress" to worse.

Yes so from rest, there is a surge it lasts seconds and then my ears ring for a while and then sometimes within minutes or hours there is nothing. What is going on?

[Jerry_NJ]

I'll give you post a "bump" to the top of the list and hope someone on an ICD will read and have some helpful experience to share.

There's nothing in your opening symptom description that makes me think "heart".  Then you tell us you have an ICD, well that is something of which I have zero experience, so I'll not try to explain anything related to that.

I assume you have discussed with your doctor(s)... are you  on any heart meds?