Table of Contents
- Atrial fibrillation (AFib) facts
- What is the normal function of the heart?
- What is the electrical function of the heart?
- What causes atrial fibrillation?
- Heart rate during AFib
- What are the symptoms of atrial fibrillation (AFib)?
- What are the risk factors for developing atrial fibrillation (AFib)?
- How is atrial fibrillation (AFib) diagnosed?
- Heart monitors and other tests
- What is the treatment for atrial fibrillation (AFib)?
- Slowing the heart rate with medications
- Anticoagulation drugs to prevent blood clots and strokes
- Who are, and who are not candidates for warfarin?
- Newer medications to prevent stroke in AFib
- Cardioversion with medications
- Other methods of converting AFib to a normal rhythm
- Risks and candidates for cardioversion
- Procedures for treating and preventing atrial fibrillation (AFib)
- Other procedures for treating and preventing atrial fibrillation
- What are the complications of atrial fibrillation (AFib)?
- What is pulmonary vein isolation?
- Who are candidates for PVI, and what are the risks?
Quick GuideAtrial Fibrillation: Heart Symptoms, Diagnosis & Treatment for AFib
What is the electrical function of the heart?
With each beat of the heart, an electrical discharge (current) passes through the electrical system of the heart. The electrical discharge causes the muscle of the atria and ventricles to contract and pump blood. The electrical system of the heart consists of the SA node (sinoatrial node), the AV node (atrioventricular node) and special tissues in the atria and the ventricles that conduct the current.
The SA node is the heart's electrical pacemaker. It is a small patch of cells located in the wall of the right atrium; the frequency with which the SA node discharges determines the rate at which the heart beats. The electrical current passes from the SA node, through the special tissues of the atria and into the AV node.
The AV node serves as an electrical relay station between the atria and the ventricles. Electrical signals from the atria must pass through the AV node to reach the ventricles.
The electrical discharges from the SA node cause the atria to contract and pump blood into the ventricles. The same discharges then pass through the AV node to reach the ventricles, traveling through the special tissues of the ventricles and causing the ventricles to contract. In a normal heart, the rate of atrial contraction is the same as the rate of ventricular contraction.
At rest, the frequency of the electrical discharges originating from the SA node is low, and the heart beats at the lower range of normal (60 to 80 beats/minute). During exercise or excitement, the frequency of discharges from the SA node increases, increasing the rate at which the heart beats. Continue Reading
UpToDate. Patient information: Atrial fibrillation (Beyond the Basics).
Wann, Samuel L., et al. "2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (Updating the 2006 Guideline): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines." Journal of the American College of Cardiology 57.2 (2011): 223-242.
7.Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762.
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19.Getyy Images / iStock
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