During Atrial Fibrillation (A-fib), the heart's upper chambers (the atria) beat irregularly or quiver, instead of beating effectively. As a result, the blood isn't pumped completely out of the atria and may pool. Pooled blood is likely to form a clot. If the clot dislodges from the atria, it can travel to the brain (or other parts of the body) and block blood flow, causing a stroke. br br Life Line Screening provides preventive health screening services for a-fib, stroke, abdominal aortic aneurysm, peripheral arterial disease, diabetes, heart disease & osteoporosis. To schedule a preventive health screening for atrial fibrillation, visit or call 1-877-237-1336.