Hi @redhound and welcome to Mayo Clinic Connect. I am sorry to hear that you have anxiety surrounding this diagnosis. You will see that I added your post to a discussion talking about aortic dissection. I did this so you can connect with the different members who have actually had an aortic dissection like @realitytest, @rickh2, @lorettat, and @cobweb

Can you share what started this intense fear of aortic dissection?

@redhound I have experienced a level of anxiety similar to yours, and the good news is that you can beat this! I did, and I figured most of it out by myself. I had fears based on early childhood adverse experiences and fears of the doctors and dentists who I thought would hurt me. I didn't have the emotional support from my parents to be able to handle it even though they told me why I had to endure something that was going to hurt. I feared pain, and started passing out at appointments when I was only 6. That became a pattern for many years on into adulthood. I got good at predicting it when I sensed the dizziness beginning and I would put my head down or lay down on the floor so I wouldn't fall and hurt myself. It didn't help that I was always made fun of for this. It is a real problem, and I was alone in trying to deal with it.

I have had chest pains similar to yours caused by stress that mimicked a heart problem and I do have a condition called thoracic outlet syndrome that increase chest tightness. My dad actually did have a heart problem and had a first heart attack at 50. I sure as heck didn't want that to happen to me, so when he had to change his diet, I did that too and started eating healthy in my twenties. Later in my life when I was in my fifties, I was evaluated by a cardiologist who told me they couldn't find any blockage and the chest pain I had was caused by stress. He said I was doing everything right and there was no reason that I should not live to be a hundred. My blood pressure would also spike when I was really scared or upset. Passing out actually is your body's way to protect itself. Blood pressure that gets too high puts pressure on the heart and arteries, and fainting causes a sudden drop in blood pressure, and you pass out temporarily because it stops sending enough blood to the brain to maintain consciousness. Too much blood pressure can cause a stroke if the arteries can't handle it. In my mind, when I was approaching the same age as my dad for when his problems started, I asked myself if this would happen to me too?

There have been 2 relatives of mine who died from an aortic dissection and an aortic aneurysm. Both were older in their 70's and 80's. A death from an aortic dissection happens quickly, often so quickly that the emergency room hasn't figured out what is happening. Actor, John Ritter died of an aortic dissection within a few hours of feeling ill on the television set. He was nauseated and sweating profusely and was taken to the ER, but they couldn't figure it out in time. My relative had been feeling tired and thought he was having an allergic reaction to spray paint. His friend took him to the ER and they didn't find anything. He was being difficult and second guessing the doctors and they released him. He mostly rested in a recliner the next day. The day after that, he was taken to a different hospital ER and was able to walk in the door, and they thought it was a heart attack at first. They did some ultrasound imaging and diagnosed the aortic dissection, and it would be 30 minutes for them to assemble a surgical team, and by then he was gone. The entire time in the ER had been just 2 hours in which he could walk in the door and die 2 hours later. The other relative was having some back pain between the shoulder blades one evening for probably a couple hours, and she wasn't as sharp cognitively which was a change from the norm. She died in a few minutes, and her spouse found her in another room and she could not be revived. They had known about the aneurysm for years, but it was inoperable and there were no symptoms.

The day that I started to turn things around for myself came because I had developed spinal cord compression from an old whiplash injury that had happened years earlier. Hearing a surgeon tell me that I had significant spinal cord compression that could be doing permanent damage and put me at risk for paralysis sent my blood pressure spiking. I had that old queasy feeling again, but there was no escape. For 4 months, every morning when I thought about having spine surgery, the fear shot through me and my blood pressure spiked (I was measuring it.) I knew that this anxiety was not only hard to live with, but I worried what it was doing to my heart. Why was I doing this to myself? How could I let this happen? I didn't want stress to cause a heart attack like it had done for my dad. That was the beginning of asking myself a lot of questions and learning how to understand my fear and re-frame my thinking.

If you begin to make friends with your fear and understand it, you can ask yourself similar questions of why? What in your past experience has caused similar feelings? How is this past experience linked to your present fear? What is the trigger that sets it off? Understand that your brain will react to stress and fear pushing aside everything else because that was a survival instinct that helped early man not get eaten by some large animal. You are going to have to give your brain some help and advice to let go of some of those episodes. I started by writing down a history of the adverse events in my life and it showed me a pattern of how and why I reacted to fear. Fears get linked in the memories in your brain because when your brain sees the old pattern, it says, let's not waste time, I know what to do, so I will react quickly. When you take the time to examine why, and understand why your brain jumped to a conclusion, you break that link and deprogram that fear. I didn't expect to accomplish that in my life, but I did, and it changed my life completely, not only giving me the confidence to address my medical issues and get care without fear, but to be more confident and content in the rest of my life. I have so much more time now, because I am not consumed with fear. That is not to say that I will never fear again, but I no longer have fear about medical issues. I also know that I have the skills to cope with and accept things, and I also have the power to alter the course of my health in the choices that I make.

I did see counselor to make sure I was on the right track before my spine surgery, and I was doing fine. One good piece of advice was that having gratitude will help chase away fear. It is a positive emotion that spreads the chemistry of the "feel good" molecules in your brain. I made it a point to see my surgeon right before the procedure and thank him for helping me. That was a really good way for both of us to head into surgery. There is of course a bit more to the story.
https://sharing.mayoclinic.org/2019/01/09/using-the-art-of-medicine-to-overcome-fear-of-surgery/
Here is another discussion about fear that may help.
https://connect.mayoclinic.org/discussion/how-can-i-defeat-my-anxiety-about-medical-tests-and-surgery/
Don't give up. You can do this. Fear does not need to control your life or influence your decisions or behavior.

Have you found a counselor that you can talk to? Will you begin a journal to record and discover the clues to your fears? What are the questions that you could ask yourself now about your fear?