Afib (Atrial fibrillation)
One of the most common heart arrhythmias is atrial fibrillation. A normal heartbeat starts with an electrical signal, which sets your heart's pumping action into motion. Blood is pushed through the uppers chambers (atria) and into the lower chambers (ventricles). The ventricles send the blood out to the rest of your body. With each beat, the atria and ventricles work together. In atrial fibrillation, however, the electrical signal misfires. The signal spreads through the atria rapidly and chaotically, causing the chambers to quiver or fibrillate. The ventricles respond in kind. And the heart's upper and lower sections fall out of sync.
The result: Blood doesn't move efficiently through the heart and out to the rest of the body.
Why is it dangerous?
The two most serious complications of atrial fibrillation are stroke and heart failure. Blood that isn't properly pumped out of the atria can pool, stagnate, and form clots. If part of a clot breaks off and travels to the brain, it can cause a stroke. Heart failure occurs when the heart works overtime to meet the body's need for blood and oxygen. It can cause fluid to accumulate in the lungs and lower limbs.