What is atrial fibrillation?

The heart is made up of four chambers. The top two chambers are called the atria and the bottom two chambers are called the ventricles. Electrical signals travel through the chambers, telling them to contract and relax (or “pump”) in a synchronized fashion. In atrial fibrillation, the electrical signals to the atria are irregular and more rapid, often described as quivering or “fibrillating”