Atrial Fibrillation (AFib)
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?
What causes atrial fibrillation?
The cause of AFib is an abnormal heart rhythm. During AFib, electrical discharges are not generated solely by the SA node. Instead, electrical discharges come from other parts of the atria. These abnormal discharges are rapid and irregular and may exceed 350 discharges per minute. The rapid and irregular discharges cause ineffective contractions of the atria. In fact, the atria quiver rather than beat as a unit. This reduces the ability of the atria to pump blood into the ventricles.
The rapid and irregular electrical discharges from the atria then pass through the AV node and into the ventricles, causing the ventricles to contract irregularly and (usually) rapidly. The contractions of the ventricles may average 150/minute, much slower than the rate in the atria. (The ventricles are unable to contract at 350/minute.) Even at an average rate of 150/minute, the ventricles may not have enough time to fill maximally with blood before the next contraction, particularly without the normal contraction of the atria. Thus, AFib decreases the amount of blood pumped by the ventricles because of their rapid rate of contraction and the absence of normal atrial contractions.Continue Reading