You can check for atrial fibrillation (afib) right now by feeling your pulse at your wrist. If the rhythm feels irregular, with beats that seem randomly spaced, too close together, or occasionally missing, that’s the hallmark sign. But a pulse check is just a starting point. Afib can also be silent, picked up by a smartwatch, or caught only after days of continuous heart monitoring.
Check Your Pulse at Home
Turn your left hand palm-side up. Place the first two fingers of your right hand on the outer edge of your left wrist, just below where your wrist meets your thumb. Slide your fingers toward the center of your wrist and press down gently until you feel a pulse. Don’t use your thumb, which has its own pulse and can throw you off.
Count the beats for a full 60 seconds. Pay close attention to whether they’re evenly spaced. A healthy heart rhythm feels steady and predictable, like a metronome. In afib, the rhythm is “irregularly irregular,” meaning there’s no pattern to the unevenness. You might feel a quick cluster of beats followed by a pause, then a single strong beat, then two fast ones. It doesn’t repeat in any recognizable cycle. If that’s what you feel, it’s worth getting a formal evaluation.
Symptoms That Point to Afib
Most people with afib do experience symptoms, though they vary depending on age, sex, and how often the episodes occur. The most commonly reported are fatigue and shortness of breath. Palpitations (a fluttering, pounding, or racing sensation in your chest) are also very common, especially in younger people and those whose afib comes and goes. Chest discomfort and dizziness round out the usual list. Women tend to experience all of these symptoms more intensely and more frequently than men.
If your afib is persistent rather than occasional, you’re more likely to notice fatigue and breathlessness than dramatic palpitations. Older adults in particular may never feel their heart flutter at all, instead noticing only that they tire easily or get winded climbing stairs.
Between 10% and 40% of people with afib have no symptoms whatsoever. This “silent” afib is concerning because the condition still raises stroke risk even when you can’t feel it. Many of these cases are discovered incidentally during a routine checkup, after a stroke, or by a wearable device.
What Smartwatches Can and Can’t Do
Modern smartwatches have become surprisingly accurate screening tools. A 2025 meta-analysis found that the Apple Watch detects afib with 94% sensitivity and 97% specificity. Samsung devices performed similarly, at 97% sensitivity and 96% specificity. The Withings ScanWatch came in at 89% sensitivity and 95% specificity. In practical terms, these devices catch the vast majority of true afib episodes and rarely flag a normal rhythm as abnormal.
That said, a smartwatch notification is not a diagnosis. These devices use optical sensors on your wrist to estimate heart rhythm, which can be thrown off by movement, a loose band, or poor circulation. They also only check intermittently, so they may miss short episodes. Think of a smartwatch alert as a strong signal to get a proper electrocardiogram (EKG), not a final answer.
Portable EKG Devices
If you want something more reliable than a smartwatch but more convenient than a doctor’s visit, personal EKG monitors bridge that gap. The most widely studied is the KardiaMobile by AliveCor, a small device with metal electrodes that pairs with your phone. You place your fingers on the electrodes for 30 seconds and get a single-lead EKG tracing on your screen, along with an automated reading of whether afib is detected.
In clinical studies, KardiaMobile’s sensitivity for detecting afib has reached 98% to 99% with specificity above 91%, though accuracy drops when afib is rare in the population being tested. One large study where only 2.7% of participants had afib found the device’s sensitivity fell to about 71%. This matters because if you’re using it as a one-time screening tool and your risk is low, a “normal” result is less reassuring than if you’re tracking frequent symptoms. These devices are FDA-cleared and available without a prescription, making them a practical option for people who want to document what’s happening during palpitations so they can show their doctor a real recording.
The Gold Standard: An EKG
A standard 12-lead EKG is what doctors use to confirm afib. The test takes about 10 seconds of recording and looks for a specific combination of features: an irregularly irregular rhythm, no visible P waves (the small electrical blip that represents the upper chambers squeezing in sync), and no stable baseline between heartbeats. When all of these are present, the diagnosis is definitive.
The catch is timing. A 10-second EKG only captures what your heart is doing right now. If your afib comes and goes, there’s a good chance your heart will be in normal rhythm during the test. This is the single biggest challenge in afib detection, and it’s why longer monitoring is often necessary.
Extended Heart Monitors
When a standard EKG comes back normal but your symptoms continue, the next step is wearing a monitor for a longer period. The options differ mainly in how long they record and how much they interfere with your daily life.
A Holter monitor is the traditional approach: a small device with wires and adhesive patches worn for 24 hours. It records every heartbeat continuously. The problem is that 24 hours often isn’t long enough. In one study comparing monitoring approaches, a standard Holter caught significant arrhythmias in only 19% of patients.
Adhesive patch monitors, worn for 7 to 14 days, perform substantially better. The same study found that a 7-day patch monitor detected significant arrhythmias in 34.5% of patients, nearly double the Holter’s yield. These patches are waterproof, wire-free, and slim enough to wear under clothing, making them far easier to tolerate for a full week. Event monitors, which can be worn for up to four weeks, extend the window further but require you to press a button when you feel symptoms, which means they can miss episodes that happen during sleep or without noticeable symptoms.
Implantable Loop Recorders
For the hardest cases, where symptoms happen only a few times a year or where doctors suspect silent afib after a stroke, an implantable loop recorder (ILR) provides continuous monitoring for up to three years. It’s a tiny device, about the size of a paper clip, inserted just under the skin of the chest in a quick outpatient procedure.
ILRs are typically recommended when shorter monitors haven’t captured anything despite ongoing symptoms, when episodes happen less than once a month, or when a patient has had a stroke with no obvious cause and doctors want to rule out hidden afib. The device automatically records abnormal rhythms and transmits data wirelessly to your medical team, so it can catch episodes you never feel.
Blood Tests as Screening Clues
No blood test can diagnose afib directly, but certain biomarkers can flag people at higher risk. The most studied is NT-proBNP, a protein released when the heart is under strain. A large meta-analysis found that elevated NT-proBNP levels are associated with a 37% higher incidence of developing afib. Markers of inflammation and subtle heart muscle injury also correlate with increased risk. These tests are most useful in population screening or when a doctor is deciding whether to pursue longer monitoring in someone with borderline symptoms. They won’t tell you whether you’re in afib right now, but they can help explain why your doctor might want to dig deeper.
Matching the Method to Your Situation
If you feel occasional palpitations and want a quick check, start with your pulse and consider a personal EKG device. If symptoms are frequent but brief, a 7-to-14-day patch monitor is the most efficient medical option. If episodes are rare or you’ve already had a stroke without a clear cause, an implantable recorder may be the only way to get a definitive answer. The key point across all of these methods is that afib is often intermittent, so a single normal test doesn’t rule it out. The longer you monitor, the more likely you are to catch it.