Atrial Fibrillation Awareness: Know the Signs, Including the Ones You Cannot Feel

A flutter in the chest while you are sitting perfectly still. A flight of stairs that leaves you winded when it never used to. Or nothing. No symptom of any kind, until a nurse takes your pulse before a routine procedure and pauses a second longer than you expected.

All three of those are atrial fibrillation. The first two send people to a doctor. The third one is the reason September exists as AFib Awareness Month.

The Condition That Often Announces Itself Too Late

Atrial fibrillation, usually shortened to AFib, is the most common sustained heart rhythm disorder in the United States, and it is considerably more common than researchers used to think. A 2024 analysis published in the Journal of the American College of Cardiology put the number of U.S. adults living with AFib at roughly 10.5 million, about three times the 3.3 million figure that had stood for two decades.

The reason awareness matters more here than it does for most conditions is what AFib does quietly. According to the Centers for Disease Control and Prevention, AFib is associated with an approximately fivefold increased risk of ischemic stroke, and it causes about one in every seven strokes. The American Heart Association notes that AFib can double the risk of death.

Those numbers do not require you to feel anything. That is the whole problem, and it is the reason this article spends most of its length on detection rather than on treatment.

What Atrial Fibrillation Actually Is

In a healthy heartbeat, the two upper chambers of the heart, the atria, contract in a coordinated squeeze that pushes blood into the lower chambers. In AFib, that coordination breaks down. The atria quiver chaotically instead of contracting, and the result is a heartbeat that is irregular and often fast.

Atrial flutter is a close relative and often gets mentioned alongside it. In flutter, the atria also beat very fast, but in an organized rhythm rather than a chaotic one. Both conditions carry stroke risk, and both are relevant to the same treatment conversations.

The American Heart Association describes AFib as progressing through four stages, from being at risk for it, to pre-AFib where structural or electrical changes are present, to diagnosed AFib, to permanent AFib that no longer responds to rhythm control. Where a person sits on that path shapes what their care looks like.

If you want the mechanics of the stroke connection in detail, our earlier article on how AFib raises stroke risk walks through what happens inside the heart when the rhythm goes irregular.

The Signs You Can Feel

The CDC lists these as the symptoms of atrial fibrillation:

• An irregular heartbeat

• Heart palpitations, described as rapid, fluttering, or pounding

• Lightheadedness

• Extreme fatigue

• Shortness of breath

• Chest pain

Two things about that list are worth saying out loud, because they are what cause people to dismiss it.

First, several of those symptoms are easy to explain away. Extreme fatigue gets blamed on a bad week. Shortness of breath gets blamed on being out of shape or on the Florida humidity. Lightheadedness gets blamed on standing up too fast. Individually, each of those explanations is often correct. Together, and especially alongside a heartbeat that does not feel steady, they are worth a conversation with a physician.

Second, AFib frequently comes and goes. An episode can last minutes or hours and then stop on its own, which means a person can feel genuinely unwell in the evening and completely normal at their appointment three days later. Feeling fine at the moment of the exam does not mean nothing happened.

The Sign You Cannot Feel

The CDC puts it plainly: some people who have AFib do not know they have it and do not have any symptoms.

This is the part of AFib awareness that actually saves people. Stroke risk in atrial fibrillation is driven by what the rhythm is doing to blood flow, not by whether the person can perceive it. Someone with no palpitations, no breathlessness, and no fatigue can be carrying the same elevated risk as someone who has felt every episode.

Silent AFib is usually found by accident: a pre-operative check, an unrelated ECG, a physical for an insurance policy, a blood pressure cuff at a pharmacy that flags an irregular pulse. Sometimes it is found after a stroke, which is the outcome the awareness month exists to prevent.

How to Check Your Own Pulse in Sixty Seconds

This is not a diagnosis, and nothing in this section replaces an evaluation. It is a thirty second habit that occasionally sends someone to a doctor who would not otherwise have gone.

1. Sit down and rest for about five minutes first. A pulse taken immediately after climbing stairs tells you very little.

2. Turn one palm face up. Place the index and middle fingers of your other hand on the thumb side of your wrist, just below the base of the thumb. Do not use your thumb, which has a pulse of its own and will confuse the count.

3. Press gently until you feel the beat.

4. Count the beats for a full sixty seconds.

Most people focus on the number, and the number does matter. A resting pulse consistently above 100 or below 60 beats per minute is worth mentioning to a physician if it is new for you.

But the more useful thing to pay attention to is the spacing. A normal pulse has a metronome quality to it, an even gap between beats. In atrial fibrillation, that spacing is unpredictable: a run of quick beats, a pause, another beat, another pause of a different length. Clinicians describe it as irregularly irregular, meaning there is no pattern to the irregularity.

If the rhythm feels chaotic rather than steady, that is a reason to make an appointment. It is not a reason to panic.

What a Smartwatch Alert Does and Does Not Tell You

A large number of people now find out about their heart rhythm from a wrist. Irregular rhythm notifications on consumer wearables have been cleared by the FDA, and they are genuinely useful. They are also widely misread in both directions.

What the alert means. It means the device detected a rhythm that looks irregular in a way consistent with atrial fibrillation, and it is telling you to get that looked at. It is a prompt, not a finding.

What it does not mean. It is not a diagnosis, and these features are not designed for people who already carry an AFib diagnosis. Equally important in the other direction: the absence of an alert is not a clean bill of health. A device that samples periodically can miss episodes entirely, so a quiet watch does not rule anything out, particularly if you are having symptoms.

What to do with one. As Houston Methodist puts it, do not brush it off. The next step is to check in with your doctor, who can order the tests needed to confirm or rule out AFib. Take a screenshot of the notification and any rhythm recording the device saved. That data gives a clinician somewhere to start.

One honest note that most articles on this subject leave out. In January 2022 the U.S. Preventive Services Task Force concluded that the current evidence is insufficient to assess the balance of benefits and harms of screening for atrial fibrillation, and issued a Grade I statement. That applies specifically to adults 50 and older who have no AFib diagnosis, no symptoms, and no history of stroke or transient ischemic attack. It expressly does not apply to anyone who has symptoms or an existing diagnosis. In other words: the evidence for routinely screening healthy, symptom-free adults is not settled, and none of that uncertainty applies once you actually have something to report.

How AFib Is Actually Diagnosed

Confirming atrial fibrillation means capturing the rhythm while it is happening. That sounds simple and often is not, because the rhythm may not be happening on the day of the appointment.

The usual sequence looks something like this:

• A standard ECG in the office. Quick, painless, and definitive if you happen to be in AFib during the recording. A normal ECG rules out AFib at that moment and nothing more.

• A wearable monitor. If symptoms are intermittent, a physician may send you home wearing a monitor. Options range from a monitor worn for a day or two, to an adhesive patch or event recorder worn for weeks, to a small implantable recorder for cases that need long observation.

• Additional testing. An echocardiogram looks at heart structure and function, and bloodwork can identify contributors such as thyroid problems.

The practical takeaway for a patient: if you were told your ECG looked fine but you are still having episodes, that is a reason to go back and ask about longer monitoring, not a reason to drop it.

When It Is an Appointment, and When It Is 911

Schedule an appointment if you notice a persistently irregular pulse, new or worsening palpitations, unexplained fatigue or breathlessness, or if a wearable device has flagged an irregular rhythm. None of those are emergencies on their own, and all of them are worth a real evaluation rather than a wait-and-see.

Call 911 immediately for chest pain or pressure, fainting or near-fainting, severe shortness of breath, or any sign of stroke.

The American Stroke Association uses B.E. F.A.S.T. for those stroke signs:

• B, Balance loss

• E, Eye or vision changes

• F, Face drooping

• A, Arm weakness

• S, Speech difficulty

• T, Time to call 911

Stroke treatment is measured in minutes. If any of those appear, call 911 rather than driving yourself or waiting to see whether it passes.

Where Clinical Research Fits In

Once AFib is diagnosed, the standard approach to lowering stroke risk is anticoagulation, medication that makes clotting less likely. It works well for a great many people. It does not work for everyone. Bleeding risk, kidney function, and interactions with other medications all leave a group of patients who carry a real stroke risk without a treatment option they can safely take.

That gap is what clinical research is currently working on.

Arrow Clinical Trials in Daytona Beach is enrolling for the AFib and Stroke Prevention Study, a Phase 3, randomized, double-blind, placebo-controlled study of abelacimab, an investigational medication given as a monthly injection. Participants are randomly assigned to receive either the investigational medication or a placebo, and everyone continues their regular medical care throughout.

The study is enrolling adults 65 and older who have been diagnosed with AFib or atrial flutter and who are considered unsuitable for standard oral blood thinners. Study-related care is provided at no cost, and participants may receive compensation for their time and travel.

Two things worth being straight about. Abelacimab is investigational, which means it is under study precisely because its effects are not yet established, and no one can tell you in advance whether it will help you. And a clinical study is not a route to getting diagnosed. If you have not been evaluated yet, the first call is to a physician, not to a research site.

If you have been diagnosed and standard blood thinners are not an option for you, that is a different conversation, and it is one worth having. Review the study and check eligibility, browse all currently enrolling studies, or call the team at (386) 278-8000. If you are new to research, how to qualify for a paid clinical trial explains what screening involves.

Frequently Asked Questions

What are the first signs of AFib?

The most commonly reported early signs are heart palpitations that feel rapid, fluttering or pounding, an irregular heartbeat, lightheadedness, extreme fatigue, shortness of breath and chest pain. Episodes often come and go rather than being constant, so feeling normal at your appointment does not mean nothing happened.

Can you have AFib and not know it?

Yes. The CDC states that some people with AFib have no symptoms and do not know they have it. Silent AFib carries stroke risk just as symptomatic AFib does, which is why it is often found during a routine exam, a pre-operative check, or an ECG ordered for an unrelated reason.

What does AFib feel like?

People describe it as a flutter, a flip-flop, a skipped beat, or a racing heart that arrives without exertion. Others feel only fatigue or breathlessness with no awareness of the heartbeat itself. When you take your pulse during an episode, the spacing between beats is typically uneven with no discernible pattern.

Can a smartwatch detect AFib?

Consumer wearables with FDA-cleared irregular rhythm notifications can flag a rhythm that looks consistent with AFib, but they do not diagnose it, and they are not intended for people who already have an AFib diagnosis. If you receive an alert, bring it to a physician who can order confirming tests. Note that no alert is not the same as no AFib, because a device can miss episodes.

How is AFib diagnosed if my ECG came back normal?

An office ECG only captures the rhythm during the recording, so it can miss intermittent AFib entirely. If symptoms continue, ask your physician about longer monitoring, which may mean a monitor worn for a day or two, an adhesive patch or event recorder worn for weeks, or in some cases a small implantable recorder.

Is there an AFib study in Daytona Beach, Florida?

Yes. Arrow Clinical Trials conducts cardiology research at its Daytona Beach site and is currently enrolling for an AFib and stroke prevention study for adults 65 and older who have been diagnosed with AFib or atrial flutter and are considered unsuitable for standard oral anticoagulants. You can browse all currently enrolling studies to see what is open now.

Get the Rhythm Checked

If any of this sounded familiar, the next step is small: take your pulse, and if the rhythm is not steady, make an appointment. AFib is far more manageable when it is found before it does damage than after.

If you have already been diagnosed and standard blood thinners are not an option for you, review the AFib and Stroke Prevention Study or contact our team. There is no cost and no obligation to find out whether you qualify.