Upon reflection on the appointment yesterday and talking with a friend of mine who is a doctor, let me try again to express my understanding of David's situation - which seems to me to be at least a bit clearer tonight.
There is no question that David has an ASD (atrial septal defect), a hole between his atria (the two upper chambers of the heart). This is something that has been there undetected all his life, but it finally got to a point that the right side of his heart became enlarged as a result, which caused blood to flow in the wrong direction, which allowed a clot that otherwise would have been filtered out by his lungs to travel to his brain, thus causing a stroke. There is no question that this hole must be closed. From what I understand, if you only have an ASD this is entirely straightforward, but, in David's case, there is "communication" in the lower chambers of the heart as well. I found out tonight, "communication" simply means a hole (i.e. when you open a window, there is "communication" between inside and outside). I remember the doctor saying in November that there was communication between his left atrium and right ventricle - I even remember him drawing a diagram of the 4 chambers of the heart and drawing an arrow from the left atrium to the right ventricle (but this sounds absurd to my doctor friend, so maybe I am remembering incorrectly). It may be that there is a hole between the two ventricles (lower chambers of the heart) that has not been detected. It is clear that there is more going on than just the one hole, the ASD. This is something that has been known since his initial tests in November, but which was not communicated clearly to us. My friend tonight expressed that once the ASD is closed more tests can be run, and it will be more clear where the other problem is, because the one problem will be taken care of - thus clearing the view in terms of blood flow and where the other issue might be.
Regardless of what else is going on, David does need the ASD closed. That is the next step, and as soon as the doctors have set up an appointment for that, we will go to Sacramento to have that done. It is our understanding that while he is there undergoing that procedure, testing will be going on at the same time to look for the other issue as well.
Well, there you have it - the situation as best I understand it right now.