My watch ECG says inconclusive
Inconclusive or unclassified means the app could not decide. Here is why that happens, how to get a cleaner recording, and why the strip is still worth saving.
From Dr. Kenny Civello, cardiologist and electrophysiologist
A watch ECG app sorts each 30 second recording into a few bins: normal rhythm, AFib, or a bad signal. When a recording does not fit any of them, the app calls it inconclusive or unclassified. It is the app saying it could not decide.
The app only knows a few patterns
It was built to tell normal rhythm from AFib. Many other rhythms, most of them harmless, fall outside what it can name.
The strip is still useful
The label is the app's guess. The tracing is the real data. A doctor can read it and often tell exactly what it shows.
It is a common result
Extra beats, a fast or slow heart rate, and movement all cause it. Many people get one now and then.
Two different problems, one word
The recording failed
A loose band, dry or sweaty skin, movement, or talking. The watch could not get a clean signal. This one you can fix. Rest your arms, snug the band, and record once more.
The rhythm was not recognized
Extra beats, atrial flutter, a pacemaker, a bundle branch block, or a heart rate outside the app's range. The signal was fine, but the app only knows a few patterns. Recording again usually gives the same answer. Save it. A doctor can read it.
Why was mine inconclusive?
Check anything that applies to you or to that recording. Nothing you enter leaves this device.
Do not record until it says normal
Here is what I see all the time. Something feels wrong. The watch says inconclusive. You record again, and again, until it finally says sinus rhythm, and that is the one you show me. But the rhythm that made you record is often the very thing that made the first ones inconclusive.
Fix the signal once
If the recording may have failed, use the checklist below and record one more time.
Then stop and save
If it still says inconclusive, more tries will not change it. Keep every strip from that episode, including the inconclusive ones.
A normal label is not the end
Sinus rhythm only covers those 30 seconds. If you felt something and the watch says normal, still tell us. A heart monitor worn for days or weeks can catch what a watch misses.
What each brand calls it
Seven brands, seven sets of words. Each also reads a different heart rate range. Oura has no ECG. Labels can change with app updates.
| Device | Normal | AFib | Heart rate out of range | Bad signal | Could not decide |
|---|---|---|---|---|---|
| Apple Watch | Sinus rhythm, 50 to 100 | Atrial fibrillation, or AFib with high heart rate up to 150 | Low or high heart rate, under 50 or over 150 | Poor recording | Inconclusive |
| Samsung Galaxy Watch | Sinus rhythm, 50 to 99 | Atrial fibrillation, or AFib with high heart rate, 100 to 150 | High heart rate, 100 to 150. Under 50 or over 150 shows inconclusive. | Poor recording | Inconclusive |
| Google Pixel Watch and Fitbit | Normal sinus rhythm, up to 120 | Atrial fibrillation | Inconclusive: High heart rate, over 120. Inconclusive: Low heart rate, under 50. | Inconclusive: Didn’t get a good reading | Inconclusive |
| Withings ScanWatch | Sinus rhythm, 50 to 99 | Atrial fibrillation, or AFib with high heart rate, 100 to 150 | Low heart rate, under 50. High heart rate, over 100. | Poor recording | Inconclusive |
| Garmin | Sinus rhythm, 50 to 100 | Atrial fibrillation, up to 120 | Heart rate too high or too low, over 120 or under 50 | Inconclusive, poor signal | Inconclusive |
| WHOOP MG | Normal sinus rhythm, 51 to 99 | Atrial fibrillation, or AFib with high heart rate, 100 to 150 | Low heart rate, 50 or below. High heart rate, over 100. | ECG reading unsuccessful | Inconclusive |
| KardiaMobile | Normal sinus rhythm, 50 to 100 | Atrial fibrillation | Bradycardia, 40 to 50. Tachycardia, 100 to 140. | Unreadable | Unclassified |
A normal rhythm at 110 beats a minute reads as normal sinus rhythm on a Pixel Watch, high heart rate on a Galaxy Watch, tachycardia on Kardia, and inconclusive on Garmin. Your heart did the same thing. The app drew its lines in a different place.
Why some apps say high or low heart rate
Each app only reads rhythms within a set heart rate range. When your rate is above or below that range, the app does not try to name the rhythm. Some apps tell you the rate was out of range. Others just say inconclusive. Either way, the recording can still be read by a doctor.
What the research shows
Two studies looked at what is really inside inconclusive strips.
It is common, especially in heart patients
In a Swiss study of 256 people having heart rhythm procedures, each wearing five devices, about 1 in 5 recordings came back inconclusive on at least one device.
There is usually a reason on the strip
In the same study, 74 percent of inconclusive strips showed something real on the ECG, like pacing, a slow electrical pathway, or extra beats. Heavy movement during the recording was the single biggest cause.
A doctor can usually read it
In a Dutch study of 2,168 people 65 and older using Kardia, 12 percent of strips came back unclassified. Heart rhythm experts could read 95 percent of those.
Updates have not fixed it
Over about two years of software updates, inconclusive rates on five devices did not change in a meaningful way.
Record a cleaner strip
Most poor and inconclusive recordings from noise can be fixed. Run through this before you record again.
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Why these steps help
A watch ECG picks up a very small electrical signal. Muscle movement, a loose band, dry skin, and nearby electrical noise all add static to it. Too much static hides the shape of each beat, and the app gives up.
Save it and bring it
Keep every recording, including the inconclusive ones.
Save the recording
Do not delete inconclusive strips. They are often the most useful ones for us to see.
Write down what you felt
Note the time, what you were doing, and any symptoms, or that you felt nothing.
Export it
Most apps let you share a recording as a PDF. The watch alert guide shows how on an iPhone.
Bring it to your visit
Have the PDFs on your phone or printed. We read the tracing itself, not just the label.
Common questions
Does inconclusive mean I have AFib?
No. It means the app could not tell. Many inconclusive strips show a normal rhythm with extra beats. Some show AFib or another rhythm. Reading the tracing is how we find out.
What does unclassified mean on KardiaMobile?
It is Kardia’s word for inconclusive. The app did not find AFib, but the strip did not fit normal, slow, or fast. Kardia says the cause can be another rhythm, a very fast or slow rate, or a noisy recording. A very noisy strip gets a different label, Unreadable. With a KardiaCare membership, the app can also name extra beats (PVCs or SVE) and a wide QRS. Save an unclassified strip and bring it to your visit. A doctor can usually read it.
What does inconclusive mean on a Garmin ECG?
The app could not sort the recording as sinus rhythm or AFib. Movement, a loose band, a pacemaker, or a rhythm the app does not know can all cause it. Garmin shows a separate result when your heart rate is under 50 or over 120. Fix the signal once, record again, then save it.
What does inconclusive mean on a Pixel Watch ECG?
The Pixel Watch and Fitbit ECG app adds a reason after the word. High heart rate means over 120. Low heart rate means under 50. Didn’t get a good reading means the signal was poor. Only the last one is likely to change if you record again. Keep the strip either way.
I have a pacemaker. Is a watch ECG still worth doing?
It can be. The app will often say inconclusive because paced beats look different from natural ones. The tracing can still show us your rhythm. Ask us whether recordings would help in your case.
My recordings are almost always inconclusive. What does that mean?
Usually something steady about your heart or your signal, like frequent extra beats, a bundle branch block, or a tremor. Bring several recordings to your visit so we can see the pattern.
How is a watch ECG different from the one in your office?
A watch records one view of your heart's electrical signal. An office ECG records twelve views at once. The watch is good for catching a rhythm at the moment you feel it. The office ECG shows more detail.
Should I keep recording until I get a clear result?
Record once more after fixing the signal. If it still says inconclusive, stop and save it. When the rhythm is the reason, more tries give the same answer, and the strips you delete may be the ones that show what happened.
My watch said normal, but I felt something. Am I fine?
Not necessarily. A normal result covers only the 30 seconds it recorded. Symptoms that come and go can be missed. Tell us what you felt and when. We may suggest a heart monitor you wear for days or weeks.
Should I buy a different device?
Not because of inconclusive results alone. Every app has the same limits. Getting a cleaner recording and having a doctor read it matters more than the brand.
More on wearables
Set up your Apple Watch to check for AFibSet up your Fitbit or Pixel Watch to check for AFibSend your Kardia EKG to your doctorMy watch says I have AFibIrregular rhythm notifications, explainedMy watch says my heart rate is high or lowMy watch says I may have sleep apneaMy watch says I may have high blood pressureFDA cleared or wellness: what the label meansWhich wearable features are FDA clearedHow I choose the wearables I recommendFind the right wearableBest smartwatch for catching AFibBest smart ring for sleep trackingBest home blood pressure monitorBest personal ECG without a smartwatchBest wearable for an older parentWhat wearable to get your parent for the holidaysBest wearable for athletesBest wearable without a screenThis page is general education for my patients. It does not replace advice from your own doctor. Watch ECG apps are not a diagnosis. Device names are trademarks of their makers. This page is not affiliated with any of them.
Based on: Joglar JA, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation. Circulation. 2024. Isenegger C, et al. Inconclusive single-lead ECGs from smart-devices: impact of baseline ECG anomalies. JACC Clin Electrophysiol. 2025. Isenegger C, et al. Accuracy of smartwatches for atrial fibrillation detection over time: insights from the Basel Wearable Study. JACC Clin Electrophysiol. 2024. Daniëls F, et al. Detection of atrial fibrillation in persons aged 65 years and above using a mobile electrocardiogram device. Neth Heart J. 2024. Device labels from FDA 510(k) summaries and maker support pages, checked October 2026.