Understanding atrial fibrillation (Afib) and its stroke risks
Atrial fibrillation (Afib) can increase stroke risk by up to 9%. Understand your risk and how to lower it with specialized care.
What is atrial fibrillation?
Atrial fibrillation, also known as Afib, is an irregular heartbeat where the heart's upper chambers beat at around 400 beats a minute, quivering instead of beating steadily.
"At that speed, the heart doesn't contract very well," says Paari Dominic, MBBS, MPH, adult cardiac electrophysiologist at University of Iowa Health Care. "It just quivers, and therefore, the blood from the top chamber doesn't get completely emptied into the bottom chamber."
While this condition can lead to complications like heart failure, blood clots, and strokes, it is the most common type of arrhythmia, an irregular heart rhythm.
How to recognize Afib?
Afib can be challenging to recognize, as some people experience no symptoms prior to a physical examination by a medical professional such as an arrhythmia specialist, also known as a cardiac electrophysiologist.
Yet, many people with Afib may identify the condition by understanding its common symptoms:
- Fatigue and weakness
- Fluttering in the chest
- Dizziness
- Shortness of breath
- Faintness
- Sweating
- Difficulty when exercising
- Chest pain or pressure
- Discomfort in the upper body
Visiting a cardiologist can help you identify your condition and recognize if you're experiencing Afib. Medical professionals use several tests to diagnose Afib, including:
- Electrocardiograms (ECG or EKG) that record electrical activity in your heart.
- Portable devices, like a Holter monitor, event recorder, or implantable loop recorder to monitor heart rhythm throughout your day.
Does Afib increase stroke risk?
Afib can significantly increase your risk of stroke. While your risk varies—depending on your age and the presence of other medical conditions like diabetes and hypertension—and it can worsen with time, stroke is still the primary risk associated with Afib.
"We have something called a CHA2DS2-VASc scoring system for the risk of stroke, which includes age, congestive heart failure, hypertension, diabetes, if you have vascular disease, like heart disease, in other areas, and previous history of stroke," says Dominic. "And that will tell us your stroke risk."
A stroke risk could range from between 1% to 1.5% and go all the way up to a 9% annual risk of stroke for certain patients.
Why does Afib increase stroke risk?
"So, the reason for stroke in Afib is twofold," says Dominic.
- During Afib, the heart can't contract properly, causing blood to quiver and pool in the heart's upper chambers, resulting in changes to your cell's properties. This can lead to clot formation originating in the heart but possibly venturing into the brain, blocking blood supply and resulting in a stroke.
- Your left atrial appendage is a small pouch within the left upper chamber of your heart that faces downward. The blood within this structure must be emptied through a contraction. Therefore, without proper contractions, blood stagnates and can result in small clots that journey to the brain, causing a stroke.
What type of stroke is associated with Afib?
An embolic stroke is associated with Afib due to the higher likelihood of clot formation within the heart's upper chambers. These clots peel off the heart's walls in pieces and can journey to any portion of the brain, unlike a thrombotic stroke, which is limited to one region of the brain.
How to manage Afib and reduce your stroke risks
For patients diagnosed with Afib, a cardiac electrophysiologist will determine your stroke risk percentage and evaluate which prevention method is best for your calculated risk:
If your risk is 2% or higher, your doctor will likely place you on blood-thinning medication to reduce the stroke risk and prevent clotting within the left atrial appendage and throughout the entire heart.
You may not be a candidate for blood thinners due to a high bleeding risk. In this case, doctors may recommend a left atrial appendage closure, where an amulet or Watchman device is placed to close off the left atrial appendage and prevent clots from venturing into the brain and causing a stroke.
When to seek medical attention
If you suspect you have Afib due to irregular heartbeats, consult your health care provider promptly to manage your stroke risk and seek a referral for a cardiac electrophysiologist to get the specialized care you deserve.
While recognizing the signs of Afib can be tricky, seek medical attention immediately if you experience chest pain, severe shortness of breath, or sudden weakness in your upper body. These may be signs of a stroke.