It accounts for more than a quarter of all ischemic, or clot-related strokes. It increases your risk of having such a stroke fivefold. And, maybe most shockingly, for many people, having a stroke is the first time they learn they may be experiencing it. It’s a cardiac condition called atrial fibrillation, commonly referred to as AFib.
AFib affects nearly 6 million people in the United States—a number that’s expected to rise to 12.1 million by 2030.
According to Rashedul Hasan, MD, a neurologist on the medical staff and medical director for the comprehensive stroke program at Baylor Scott & White Medical Center — Plano and director of the telestroke program for the northeast region, AFib is the most common type of heart arrhythmia. If someone has an arrhythmia, it means their heart beats too fast, too slowly or in an irregular way.
When a person has atrial fibrillation, the normal beating in the upper chamber of the heart (the atria) is irregular, quivering or fluttering rather than pumping. Because of this, the blood does not move effectively from the atria to the lower chambers of the heart (the ventricles).
Blood stays in the heart, growing stagnant, and that can lead to blood clot formation. Eventually, those clots can break loose and travel to the brain causing an ischemic stroke.
Related: Are you at risk for stroke?
Diagnosing atrial fibrillation, or AFib
So, why don’t most people know they have AFib until they have a stroke?
Dr. Hasan said that diagnosing one of the most common types of AFib, called paroxysmal atrial fibrillation, can be incredibly challenging. That’s because paroxysmal AFib, which accounts for about 40 percent of all AFib cases, comes and goes with arrhythmia that is brief and intermittent and could last 24 hours to a week before your heart returns to its normal rhythm. The aFib might not happen again until a month, six months or even a year later.
“It’s completely unpredictable,” Dr. Hasan said. “We do not know when it will happen and that makes it very hard to detect, because if you check an EKG, you will find that the heart rhythm is normal if you are not checking during that short time the person is in AFib.”
Other types of AFib—persistent (lasting longer than a week but restored with treatment) and permanent (which cannot be restored with treatment)—will frequently be detected by EKG or may cause symptoms such as a pounding heartbeat (palpitations), shortness of breath, weakness, or dizziness.
But paroxysmal AFib is typically asymptomatic, which means there’s nothing that prompts you to get your heart rate checked.
Monitoring your heart rate
Unfortunately, often the first trigger that you need to be monitored for AFib is an ischemic stroke that occurs in a particular location in the brain. If you have a stroke that your medical team suspects was caused by AFib, they can monitor your heart rate and rhythm in one of two ways.
An external monitor, as its name implies, is a device you wear or carry with you for 14-30 days while it monitors your heart rate 24 hours a day. After that time period, you return the device to your cardiologist and they look through the data to see if any atrial fibrillation was detected.
The downfall of this technique, according to Dr. Hasan, is that paroxysmal AFib is so sporadic that you may not have any events in those 30 days. If that’s the case, your test results will still be normal.
If the above happens, your cardiologist might implant an internal monitorunder your skin on the left side of your chest. This device, called a loop recorder, checks your heart rate and rhythm 24 hours a day for three to four years, depending on its battery life.
Each monitor comes with receptor or hub that you keep in your home, and when you get close to that hub each night, the device will upload the whole day’s recording to the cloud for your cardiologist to review.
Two approaches to treating AFib
If one of these monitors confirms you are experiencing AFib, Dr. Hasan said there are two complementary treatment approaches that should be used together: One to bring your heart rate and rhythm under control so there is no arrhythmia, and one to prevent blood clots from forming in the heart.
Both strategies rely primarily on medication to achieve results. Beta blockers and calcium channel blockers are often prescribed to help control heart rate and rhythm while blood thinners, such as aspirin, clopidogrel (Plavix), or anticoagulants including warfarin (Coumadin), rivaroxaban (Xarelto), dabigatran (Pradaxa) or apixaban (Eliquis), are used to prevent blood clots.
What if your doctor recommends you avoid the use of blood thinners? Some people cannot use blood thinners because of risk factors such as anemia, a GI bleed or a high risk of fall. If that’s you, you may be a candidate for an implanted device that can help prevent blood clot formation by cutting off access to the left atrial appendage where most of the blood pools during AFib.
To try to control heart rate and rhythm, interventional procedures like radiofrequency catheter ablation or electrical cardioversion also may be appropriate. Your cardiologist can help you determine which treatment options may be right for you.
Reducing your risk of future strokes
Unfortunately, once you have a stroke, you are at a higher risk for having another. Although that’s true for everyone who has experienced a stroke, the risk of recurrence is particularly strong for people with untreated AFib.
“But as long as you keep your heart rhythm under control and take blood thinners to prevent blood clots, your risk is as low as anyone else’s,” Dr. Hasan said.
Even if you work with your doctor to get your AFib under control, it’s important to remember that there are many other risk factors for stroke, including:
- High blood pressure
- High cholesterol
“If you know that you have atrial fibrillation and you take care of it, and then think you are immune to stroke, unfortunately, that’s not the case,” he said. “You have to take care of all your risk factors.”
That means working with your physician to manage symptoms and make healthy lifestyle choices, such as:
- Maintain a healthy weight
- Eat a healthy, balanced diet
- Limit alcohol intake
- Get regular exercise