Atrial Fibrillation Part I of II
The most common abnormal heart rhythm is atrial fibrillation (AFib). Normal hearts have the four chambers beating in a rhythmic steady pattern. AFib is an irregular rhythm where the atria (upper chambers of the heart) fibrillate (twitch or quiver quickly).
This irregular heart rhythm may lead to symptoms that adversely impact the quality of life in people. Interestingly, some people don’t experience any symptoms. AFib on its own is not life threatening. However, if afib is left untreated, the side effects can be life threatening, leading to heart failure or stroke. This makes treating and identifying AFib so important.
What is Atrial Fibrillation?
A normal heartbeat starts as a single electrical impulse that originates from the atria. The impulse emits an electrical pulse that enables the atria to contract and move blood into the lower ventricles. Next, the electrical current passes through the AV node (the electrical bridge between the lower and upper heart chambers), causing the ventricles to contract and then relax in a rhythmic, steady sequence. This allows blood to be drawn into the heart and pushed back out to the brain and body. When AFib occurs, the electrical impulse doesn’t follow this sequence. Instead of a single impulse moving through the heart, many impulses begin in the atria and one of them gets through the AV node. This happens for two main reasons:
- First, the heart’s structure and its electrical pathway may change over time especially when we get older.
- Second, when the electrical pathway changes, extra “triggers” may develop. Triggers are electrical circuits that send extra impulses at a faster than normal rate.
These extra impulses try to get through the AV node and cause the atria to fibrillate, twitch or quiver, in a disorganized, fast way.
Types of Atrial Fibrillation
Paroxysmal AF – AFib that occurs periodically. Paroxysmal AFib will stop by itself and return to normal sinus rhythm. AFib may last for any length of time (from seconds to days) before the heart returns to normal sinus rhythm. People with paroxysmal AFib are more likely to experience symptoms. This is because as the heart goes in and out of AFib, the heart rate may change from fast to fast and back again in short periods of time.
Persistent AF – AFib that can’t stop by itself. A special type of electrical shock, called cardioversion, or medications are used to return the heart’s rhythm to a normal rhythm. Without treatment, the heart will stay in Afib.
Permanent AF – AFib that cannot be corrected to normal sinus rhythm. C ontrolled electrical shock or medications can’t help return the heart to a normal rhythm.
What are Risk Factors to Developing Atrial Fibrillation?
Even when one lives a healthy life with no other medical problems, Atrial Fibrillation (AFib) may develop. The most common risk factors are the following:
- 60 years of age or older
- Diabetes
- Coronary artery disease
- Congestive heart failure
- Prior open-heart surgery
- Thyroid disease
- Sleep apnea
- Serious illness or infection
- High blood pressure
- Prior heart attacks
- Structural heart disease (congenital defects or valve abnormalities)
- Untreated atrial flutter (another abnormal heart rhythm)
- Chronic lung disease
- Excessive stimulant or alcohol use
