My SIL is having a WATCHMAN Left Atrial Appendage Closure inserted next month. I have been trying to understand the mechanics of this AFib mitigation solution by looking things up in google and wikipedia, and have made some progress, but I still have some details that my google-fu has not been able to find.
Basically, how does AFib cause a clot to enter the bloodstream, and what role is the Left Atrial Appendage believed to play in this process?
(I already have gleaned that it does, and that closing it off using a method such as the WATCHMAN device is a helpful way of lowering the risk that AFib poses. Also, I have gathered that the Left Atrial Appendage is not thought to have any essential function to perform, so walling it off is considered unlikely to introduce any new problems for the patient.)
So, any cardiologists on the Dope want to show off? TIA.
I have A-fib and this is the first I ever heard of this. As my doctor explained, the ventricle is not contracting properly, so blood doesn’t move and eventually clots. There is a non-trivial chance that a clot might break off and float up to the brain to cause a stroke. I take a blood thinner to minimize the chance of that, but I would certainly like to skip it. Among other things the drug can affect the liver and I have to have my blood tested twice a year for liver enzymes.
As far as I can tell, there are no overt symptoms, so walling it off should have no special effect. Perhaps I am slower from it, but at 80, I am supposed to be slowing down, no?
clots are formed within the blood vessels, with a-fib, the clot can form attached to the inside lining of the heart (mural thrombi). When and if these blood clots break up they could go anywhere in the body, causing trouble by stopping blood flow wherever they lodge.
more here: Thrombus
IANAC
Atrial fibrillation is the top chamber of your heart essentially quivering in a disorganized fashion. Fortunately the vast majority of the pumping function of the heart is done by the ventricles, so the loss of it isn’t too big of a deal.
This quivering however can lead to a significant slowing of the blood in the atria, particularly in the left atrial appendage. The left atrial appendage is sort of like a pocket of the left atrium that sticks out and over the side of the heart. It varies significantly from person to person, including in the shape, size, and overall volume of the appendage, but it is a spot where blood can slow significantly when the atrium is fibrillating. That slowing leads to higher risk of clot formation. Even for people who go in and out of atrial fibrillation, also known as paroxysmal atrial fibrillation, there is a significantly elevated risk of clot formation because there can be atrial stunning after conversion from fibrillation to normal rhythm. This means that even though the electrical activity of the atrium is normal, i.e. if you get an EKG it’ll look like a normal sinus rhythm, the atrial contraction itself is still abnormal.
The Watchman device is part of a class of left atrial appendage occlusion devices. These are usually reserved for patients with atrial fibrillation, at high risk of clot formation and thus stroke, but who cannot take blood thinners for some reason. The device is put in and essentially blocks the opening of the appendage to the rest of the atrium to ideally remove the risk of clot formation. It is not perfect, and it is certainly still possible to form clots despite that, but it is better protection than nothing.
As for how clots from the left atrium can cause stroke, it’s due to the normal pathway of blood. Blood travels from the left atrium to the left ventricle to the aorta, and from there it can go up to the brain causing strokes, or out to the GI tract causing mesenteric ischemia, or to the kidneys, or anywhere except (in most cases) the lungs.
Many thanks to all respondents, esp. audiobottle. I now feel equipped to explain to kaylasmom what is going on with her sister, and the significance of the corrective measure we’ve been hearing about.