Heart Anatomy and Rhythm

Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting an estimated 4 million people in the United States. Under normal conditions, the atria, or upper chambers of the heart, contract in a coordinated fashion to pump blood into the ventricles, or lower chambers, which then contract synchronously to pump blood through the lungs and to the rest of the body. The origin of the heartbeat is located in the sinoatrial node, at the junction of the superior vena cava with the right atrium. The atria then contract to force blood into the ventricles, effectively priming them for efficient pumping of blood to the lungs and body. The impulse from the atria travels to the atrioventricular (AV) node, which serves as the conduit to initiate contraction of the ventricles.

In atrial fibrillation, this coordinated, rhythmic contraction of the atria is replaced by rapid, disordered movements. The atria become ineffectual at pumping blood into the ventricles, resulting in a roughly 30% drop in cardiac output. Moreover, ventricular contraction – the heartbeat – becomes irregular and often rapid, causing the unpleasant palpitations experienced by many patients. The overall effect is a decline in the heart's function, resulting in the typical symptoms such as fatigue, shortness of breath, and even fainting.

For more details about atrial fibrillation and heart anatomy, request a phone consultation with Dr. John Sirak or call his appointment phone at (614) 366-7414. He is happy to educate people living with AF who want to learn more about the condition.