How to Know It's Atrial Fibrillation

Atrial fibrillation can be scary and cause fear and anxiety. It’s important that it be diagnosed and treated promptly. Failure to treat your afib can be life-threatening.

What are the symptoms of atrial fibrillation? How would you know to suspect it? What does it feel like?


When you have atrial fibrillation, you might notice a skipped heartbeat, and then feel a thud or thump, followed by your heart racing for an extended amount of time. Or you might feel heart palpitations or fluttering or jumping of your heart. Or you might experience sweating or chest pain, mimicking a heart attack. Or you may find that your pulse, instead of being strong and regular, is instead erratic or weak. Or atrial fibrillation may be so subtle that you don’t feel an irregular heartbeat, but you may realize that you’re dizzy, weak, tired, or breathless.

If you have atrial fibrillation that starts and stops, you may feel drained after an episode, but if you have continuous atrial fibrillation, you may not even realize what it is and only be aware that you just don’t have as much energy as usual or that you don’t feel like yourself. One afib patient simply described it as feeling like having “diminished capacity.”

If you’ve experienced these symptoms, it’s important to tell your doctor about them and to ask about tests to find out if you have atrial fibrillation or any irregular heartbeat or cardiac arrhythmia. The sooner you are diagnosed, the less unchecked damage it will do.

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Diagnosing Atrial Fibrillation

You or your doctor may suspect that you have atrial fibrillation because of hearing or experiencing an unusual heartbeat or a rapid heart rate. There are several ways to verify it.

Typically, afib is diagnosed by a simple EKG or ECG (electrocardiogram) where several electrodes are placed on your skin to measure and record your heart’s electrical activity in wavelengths. It is painless and takes only a few minutes as you lie down for the test to be administered.

You must be undergoing an episode of afib at the time of the EKG in order for it to be seen on the readout. This works best for patients in persistent or longstanding persistent atrial fibrillation.

If your afib episodes are intermittent, as with paroxysmal atrial fibrillation, then they most likely will not be recorded on the EKG and you may need to wear a small portable electrocardiogram device, called a Holter Monitor, for 24–48 hours in order for your episodes to be captured.

In some cases, episodes may be so sporadic or infrequent that it’s unlikely that they will be captured at all on an EKG or Holter monitor. In those cases, you may wear an event monitor, which you activate or that activates by itself when an episode occurs, to record abnormal heart rhythms that may confirm atrial fibrillation.

There are other tests that may be used for more in-depth diagnosis. For example, if atrial fibrillation is related to exercise, a treadmill stress test may be used to diagnose it. Or for infrequent episodes, a more detailed electrophysiologic study with catheters may be done in the lab. For electrophysiologic studies, the heart is stimulated to induce erratic beats and then certain drugs can be tested to determine their suitability for treating the atrial fibrillation.

To learn more about the progressive nature of atrial fibrillation, see How Atrial Fibrillation Progresses.

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