The heart’s job is to pump blood through your body. The heart’s electrical system triggers the heart to pump. The pulse or heartbeat is what you feel when the heart’s lower chambers, ventricles, push blood out of the heart through the blood vessels.
The normal heart beat is regular (no skipping), and has a rate between 60 to 100 beats per minute. When you rest your heart rate slows down, when you are active your heart rate goes up.
The Heart’s Electrical System Figure 1: Inside of heart
The electrical signal starts in the heart’s right upper chamber (the right atrium) at the sinus node and then spreads to the other upper chamber (the left atrium). The signal is then collected at the center of the heart at the AV node. The AV node is the only electrical connection from the upper chambers (atria) to the lower chambers (ventricles) in the normal heart. From the AV node, the signal speeds along special nerves call the right and left bundle branches into the lower chambers (the ventricles). The electrical signal triggers the ventricles to pump blood to the body. (See Figure 1: picture of the inside of the heart)
What is atrial fibrillation?
Atrial fibrillation is an irregular and often fast heartbeat triggered from the upper heart chambers, the atria. Treating atrial fibrillation is important for several reasons. If you have a fast heartbeat, you may feel lightheaded, dizzy, and weak. An irregular heartbeat can also increase your risk for heart failure. It can cause blood clots, which can travel from your heart to your brain and cause a stroke. Atrial fibrillation is the most common arrhythmia in humans.
The atrial electrical signal in atrial fibrillation is extremely disorganized and very rapid. Under normal circumstances these chambers generate 60 impulses per minute, in atrial fibrillation they generate up to 400 impulses per minute. These signals normally generate a single smooth electrical wave triggering the heart to beat in an orderly fashion. In atrial fibrillation the wave is chaotic and does not allow the heart to beat in an organized fashion (see Figure 2). The atrial electrical signals trigger the lower heart chambers (ventricles) to pump faster and irregular, this makes your heartbeat faster and irregular. People with atrial fibrillation often have symptoms of fatigue, shortness of breath, chest tightness or lightheadedness.
Figure 2: Atrial Fibrillation irregular rhythm.