Atrial fibrillation: symptoms, stroke risk, treatment

In short

• The main danger of AFib is ischemic stroke. The CDC says AFib causes about 1 in 7 strokes, and those strokes tend to be more severe.
• Some people have no symptoms, and the rhythm is found on a routine check.
• Diagnosis needs an EKG recording, sometimes with a monitor you wear for longer.
• Blood thinners lower stroke risk but carry a bleeding risk, so a clinician decides who needs them.
• Weight, alcohol, sleep apnea and blood pressure all affect how often episodes happen.

What happens in the heart

In AFib the upper chambers of the heart beat irregularly and out of step with the lower chambers, so blood does not flow as well into the lower chambers. The heart may beat much faster than normal. It can come in brief episodes or be permanent.

The NHLBI says it affects more than 2 million US adults and that risk rises with age. Because blood can pool in the heart, clots can form, travel and cause a stroke. For some people, episodes become more frequent and longer over time.

Symptoms

• An irregular, unsteady pulse, or palpitations such as fluttering, pounding or skipped beats.
• Fatigue, which the NHLBI calls the most common symptom.
• Shortness of breath, especially when exercising or lying down.
• Dizziness or lightheadedness, and sometimes fainting.
• Chest pain or tightness.
• No symptoms at all, which makes it hard to diagnose.

Writing down when symptoms occur, how long they last and what you feel helps your clinician. Some rhythm-recording devices work much like an EKG, so ask your provider whether yours is useful, because a device alert is not a diagnosis.

Causes and risk factors

AFib comes from a problem with the heart's electrical system. The CDC lists these risk factors:

• Advancing age.
• High blood pressure.
• Obesity.
• Diabetes.
• Heart failure or ischemic heart disease.
• Hyperthyroidism and chronic kidney disease.
• Moderate to heavy alcohol use and smoking.
• Enlargement of the left-side heart chambers.

The NHS adds endurance sports and certain medicines to the list.

What you can do yourself

• Reach a healthy weight. It can reduce how severe and how frequent episodes are.
• Limit or avoid alcohol and stimulants that may raise the heart rate.
• Be physically active, manage stress and quit smoking. The NHS suggests 150 minutes of moderate exercise a week and avoiding overexertion.
• Follow a heart-healthy eating pattern such as the DASH plan.
• Get conditions such as sleep apnea, high blood pressure and an overactive thyroid treated.
• Notice triggers such as caffeine, dehydration or poor sleep.

Lifestyle changes are part of treatment, not an extra, and they work alongside medicine.

When to see a doctor, and red flags

See a primary care provider if you think you have symptoms, if palpitations keep happening or get worse, or if treatment is not helping. Bring your notes on episodes and a list of every medicine and supplement you take.

Call 911 for a fast or irregular heartbeat with chest pain, shortness of breath, fainting, weakness or numbness on one side, confusion or speech difficulty. The WHO lists sudden weakness of the face, arm or leg on one side, numbness, confusion, trouble seeing or walking, a severe headache with no known cause and fainting as stroke signs. Do not drive yourself.

If you take a blood thinner, unusual or heavy bleeding also needs urgent care.

How a clinician confirms it

A provider uses your history, an exam and an EKG, which records the heart's electrical activity. Holter or event monitors and loop recorders track the rhythm for longer when episodes come and go.

Blood tests check substances such as potassium and thyroid hormone and show how well the liver and kidneys work. An echocardiogram looks at valves, chamber size and pumping, and can find clots in the heart. Your provider also looks for a disease causing AFib and assesses your risk of dangerous clots.

Treatment options in general terms

• Blood thinners such as warfarin or the newer direct oral anticoagulants lower stroke risk, at the cost of a bleeding risk. They are taken exactly as prescribed.
• Rate control: beta blockers or calcium channel blockers slow the heart rate. They are not suitable for everyone.
• Rhythm control: medicines, electrical cardioversion or catheter ablation aim to restore a normal rhythm. Ablation is not always successful, and AFib is most likely to return in the first few weeks.
• Left atrial appendage closure can help prevent clots when blood thinners cannot be used.
• Treating the causes, such as obesity, sleep apnea or an overactive thyroid.

The NHS says there is currently no way to remove atrial fibrillation for good, but treatment can manage symptoms and reduce the risk of clots, stroke and heart failure.

What to expect over time

AFib sometimes goes away on its own, and for other people it is a long-term condition. The NHLBI says that untreated or undiagnosed AFib can lead to stroke and heart failure, which it calls potentially life-threatening, so a diagnosis is a reason to act and not a reason to panic.

Treatment is usually a combination: medicine to prevent clots, medicine or procedures for the rhythm or rate, and changes that reduce the triggers. The plan is reviewed over time, because episodes can become more frequent and longer, and the right mix often changes with age and other health conditions.

Questions and answers

Sources

1. CDC — About Atrial Fibrillation
2. NHLBI — Atrial Fibrillation
3. NHLBI — Atrial Fibrillation: Treatment
4. NHLBI — Atrial Fibrillation: Diagnosis
5. NHS — Atrial fibrillation
6. WHO — Cardiovascular diseases fact sheet

Sources checked on 29 October 2026.