What are the risks of untreated A Fib?
Question: What are the risks of untreated A Fib?
Answer: Stroke and congestive heart failure are the two most important associated consequences of atrial fibrillation, and are the reasons why the treatment this heart rhythm disorder is important.
Stroke can occur because the top chamber of the heart is in a very chaotic and rapid rhythm. When this occurs, the top chambers are not able to squeeze and pump the blood as it is designed to do. By nature, when the blood flow slows, it has the tendency to form a clot.
So when the blood flow slows down inside the heart top chambers, it may predispose the formation of the clot. The risk of stroke has been well studies, and there are risk factors that increase the likelihood of stroke that has been identified. These risk factors are:
- Congestive heart failure
- Age greater than 65 years
- High blood pressure
- History of prior stroke
In patients without any of these risk factors, the risk of stroke can be as low as 0.5 to 2 percent per year, which is not significantly increased compared to that of general population. However, in those with significant risk factors, the risk of stroke can be as high as 5-15 percent each year.
While returning the heart rhythm to normal will reduce the risk of stroke, the only treatment that has been studied in long-term to reduce the risk of stroke is keeping the blood "thin" by using an anticoagulant medication such as warfarin.
Congestive heart failure may also be caused by atrial fibrillation, a condition called "tachycardia induced cardiomyopathy." When the main chamber of the heart has been pumping for a long time at such a rapid heart rate induced by the atrial fibrillation, the heart muscle can become very weak and cause congestive heart failure. Medication are often required to control the heart rate to below 100 beats per minute, to reduce the risk of the congestive heart failure.