@mikeyp, I ran across some added questions to raise with your cardiologist-led medical team. The questions were suggested by a symptom-checker on the WebMD web site. Here's the extract relating to "aortic dissection" in which the lining of the aorta (or a major artery near the heart or kidneys) separates from the wall of the vessel:

"Virtually everyone who has an aortic dissection experiences pain—typically sudden, excruciating pain, often described as tearing or ripping. Some people may faint as a result of the pain. Most commonly, the pain is felt across the chest but is often also felt in the back between the shoulder blades.

"The distinctive symptoms of an aortic dissection usually make the diagnosis obvious to doctors . . . In about two thirds of people with aortic dissection, pulses in the arms and legs are diminished or absent. Depending on the location of the dissection along the aorta, there may be a difference in blood pressure between the right and left arm. A dissection that is moving backward toward the heart may cause a murmur that can be heard through a stethoscope.

"Chest x-rays are the first step in detecting aortic dissection. X-rays show a widened aorta in 90% of people with symptoms. However, this finding may be due to other disorders. Computed tomography (CT) done after injecting a contrast agent (dye) can quickly and reliably detect aortic dissection and thus is useful in an emergency. Standard or transesophageal echocardiography or magnetic resonance angiography can also reliably detect aortic dissections, even very small ones."

Have you had 1) transesophageal echocardiography or 2) standard transesophageal echocardioigraphy or 3) magnet resonance angiography (MRA) to check out the major arteries on and around your heart?