Can You Have AFib and Not Know It?

Medically Reviewed by James Beckerman, MD, FACC on April 12, 2021

Atrial fibrillation, or AFib, can cause subtle symptoms that come and go. The signs can be so vague that you don’t think they’re caused by a heart condition. You may think you’re out of shape or just don’t feel like yourself.

But you could have AFib and not even know it. Some people have no symptoms at all. You might hear it called silent AFib.

Why an AFib Diagnosis Matters

When you have this common type of irregular heartbeat, your heart’s upper chambers do not contract normally. Clots can form and then travel to your brain to cause a stroke.

Your doctor may pick up signs of AFib at a regular physical. Tests like electrocardiogram (EKG or ECG) track the electrical signals your heart makes as it beats. This and other tests are used to diagnose AFib.

For some people, AFib can go away on its own. But others will need treatment to prevent blood clots and strokes.

What Are the Symptoms?

AFib has many possible symptoms. Some are so subtle they may be confusing. You may think you’re tired or short of breath because you’re older. Or you may just not feel like yourself.

Any of these could be signs of AFib:

  • Fatigue or lack of energy
  • Heartbeat that races, pounds, or flutters
  • Quick or uneven pulse
  • Shortness of breath
  • Have to pee more often
  • Feel dizzy, faint, or lightheaded
  • Sweating
  • Weakness
  • Pain, pressure, or tightness in your chest

Are You at Higher Risk for AFib?

Whether or not you notice any symptoms, you may be more likely to get AFib if you have any of these risk factors:

What Can Happen if AFib Isn’t Treated?

Even if it comes and goes, or if there are no symptoms, AFib is risky. Untreated AFib can lead to blood clots that could cause a stroke. Your odds of having a stroke are the same as someone who does have symptoms.

AFib’s rapid heartbeat can weaken your heart muscle. This can lead to heart failure. That’s when your heart can’t pump enough blood to your organs. Heart failure causes severe fatigue, weakness, and fluid buildup in your legs and feet.

Treatments for AFib can help you reset your quick or irregular heartbeat. This may help prevent blood clots and lower your stroke risk.

New Tools to Check for Signs of AFib

Your doctor tests your heart rate and rhythm to diagnose AFib. You may need to wear a heart monitor for a few days, weeks, or all the time to track your heart’s activity.

Can you track your heart rate or rhythm on your own? Some newer devices that you wear on your wrist or slip into your pocket could alert you and your doctor to possible AFib:

Heart rate trackers. Some gadgets you wear on your wrist like a bracelet or smartwatch can track your heart rate and rhythm through a monitor next to your skin. Wristband trackers aren’t always accurate and don’t pick up AFib. A better wearable monitor is a patch stuck on the skin of your chest. It records your heart rate accurately over days or weeks.

Heart-smart watches. Another smartwatch app tracks your heart rate and rhythm with a flash of light against the skin of your wrist. This picks up changes in blood flow. If the app senses that your heart rhythm is off, it alerts you to take a quick EKG by pressing your finger to an electrode on the watch. It will alert you that you may have AFib and need to tell your doctor.

What to Do if You Think You Have AFib

Make an appointment with your doctor if you have symptoms that could be AFib, especially if you have any risk factors. The doctor can diagnose AFib and prescribe any treatments you need.

If you feel chest pain or pressure, it could be a heart attack. Don’t wait to tell your doctor at your next appointment. Call 911 or go to the emergency room right away.

Show Sources

SOURCES: “Can Atrial Fibrillation Be Managed?” “How to Know It’s Atrial Fibrillation,” “Why Is Atrial Fibrillation a Problem?”

Mayo Clinic: “Atrial fibrillation,” “Atrial Fibrillation Won’t Cause Heart Attack but Can Lead to Other Serious Complications.”

Journal of Atrial Fibrillation: “Silent Atrial Fibrillation: A Critical Review.”

American Heart Association: “Warning Signs of a Heart Attack.”

Heart Rhythm Society: “Complications from Atrial Fibrillation,” “Diagnosing Atrial Fibrillation,” “Risk Factors for Atrial Fibrillation (AFib),” “Symptoms of AFib.”

Cleveland Clinic: “Smartwatch Technology Detects AFib Prior to Cardioversion.”

American College of Cardiology: “ECG on Smartwatch Accurately Detects AFib.”

Journal of the American Medical Association: “Effects of a Home-Based Wearable Continuous ECG Monitoring Patch on Detection of Undiagnosed Atrial Fibrillation.”

Franciscan Health: “New Atrial Fibrillation (AFib) Apps Track Irregular Heartbeats.”

Journal of the American Heart Association: “Contact-Free Screening of Atrial Fibrillation by a Smartphone Using Facial Pulsatile Photoplethysmographic Signals.”

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