How Accurate the ECG Is on Your Apple Watch | Qaly (2024)

Got other questions on your Apple Watch?See the complete set of Qaly guides on Apple Watch:

  • How to Install the ECGApp on Your Apple Watch
  • How to Take an ECG with Your Apple Watch
  • How to Set Up High Heart Rate Notifications on Your Apple Watch
  • How to Set Up Low Heart Rate Notifications on Your Apple Watch
  • What Poor Recording ECGMeans on Your Apple Watch
  • What Inconclusive ECGMeans on Your Apple Watch
  • What Low Heart Rate ECG Means on Your Apple Watch
  • What High Heart Rate ECG Means on Your Apple Watch
  • How to Read an ECG:Stanford Cardiologist Explains
  • The Ultimate Cardiologist's Guide to the Smartwatch ECG

Introduction

So you have an Apple Watch ECG, or you're thinking about getting one, and now you're wondering "How accurate is the Apple Watch ECG?" Or, you might be thinking, "Is the Apple Watch ECG accuracy high enough to catch abnormal heart rhythms and irregular heartbeats?" In this guide, we'll explore if the Apple Watch ECG is accurate, what its limitations are, and how you might use it to stay heart healthy. Let's dive in.

What's an Electrocardiogram?

Before diving into accuracy of your Apple Watch's electrocardiogram, or ECG, it's important to understand what exactly it is. (If you're confident in your understanding of an ECG, though, skip on ahead to the next section).

To start, remember how your heart beats?It produces an electrical signal, which squeezes and unsqueezes your heart, which in turn pumps your blood to your lungs for oxygen and then out to the rest of your body.

As that electrical signal flows through your heart, your ECGon your watch sees it, and shows it to you as those awesome-looking waves you know as an ECG. Every time your heart completes one heartbeat, it completes one full cycle of that electrical signal flowing through your heart. And as that electrical signal flows through your heart, it produces different waves on your ECG that capture the squeezing and relaxing of your heart with each heartbeat. If your heart's electrical signal moves irregularly through your heart, it likely means your heart has an abnormal heart rhythm, or arrhythmia. As a result, you'll see an irregular ECG on your watch.

The built-in electrodes in the Apple Watch ECG work with the Apple Watch ECG app to read your heart's electrical signals. If you remember from your physics or electronics course in school, you’ll want to create a circuit for an electrical signal to be able to flow through. By closing the circuit on your Apple Watch with your finger on the Digital Crown, your watch captures the electrical impulses from your heartbeat and translates them into an ECG waveform on your Apple Watch (Series 4, Series 5, Series 6, Series 7, Series 8, or Ultra). Here's how to take an Apple Watch ECG, and how to install the ECG app on your Apple Watch.

How Accurate the ECG Is on Your Apple Watch | Qaly (1)

So Is the Apple Watch ECG Accurate?

In short, very. One study co-authored and published in the New England Journal of Medicine by Stanford Associate Professor of Medicine and Qaly Co-Founder Dr. Marco Perez, demonstrated that the Apple Watch could accurately detect AFib in 84% of cases when compared to a traditional 12-lead ECG. Moreover, in 2020 during the COVID-19 national emergency in the U.S., the FDA published guidance giving clearance for Apple Watch ECG app to “serve as a substitute for in-clinic diagnostic testing,” so that healthcare providers could “use it for clinical use cases where a single-Lead or Lead I ECG test can help effectively diagnose certain arrhythmias or manage related conditions.”

How Accurate the ECG Is on Your Apple Watch | Qaly (2)

What Are the Limitations of the Apple Watch ECG?

Here are the limitations of the Apple Watch ECG hardware sensor:

  • It can have a low voltage.
  • It can have artifacts.
  • It can be unreadable or noisy as a Poor Recording ECG.

Here are the limitations of the Apple Watch ECG software app, that analyzes the Apple Watch ECG sensor data:

  • It does not diagnose, and it should not be relied upon to replace or constitute professional medical care or attention by a qualified healthcare provider.
  • It can showan Inconclusive ECG.
  • It cannot detect Afib under 50 bpm.
  • It cannot detect Afib above 120 bpm on ECGversion 1, and above 150 bpm on ECGversion 2.
  • It cannot detect arrhythmias other than Afib.
  • It cannot detect heart attacks, blood clots, stroke, or other heart-related conditions.

How Accurate the ECG Is on Your Apple Watch | Qaly (3)

ShouldIUse the Apple Watch ECG?

The Afib ECG Apple Watch feature is a great tool if you're monitoring your Afib; however, it's hard to understand your ECG for other abnormal heart rhythms and heart palpitations like rapid or skipped heartbeats. Moreover, many people have told the team at Qaly(you can find us on App Store or Play Store) that they experience a high false-positive rate with the Apple Watch ECG atrial fibrillation feature. False-positive means that your watch says you have Afib when you really don't. This can be a really scary and confusing experience for people, causing unnecessary anxiety. With that said, the Apple Watch ECG accuracy, while not perfect, has proven itself to be significantly reliable, and it provides a substantial benefit for people with Afib or at risk of Afib. You may even want to learn how to read an ECG.

As always, if you're experiencing symptoms, discuss them with your healthcare provider as soon as possible to rule out underlying heart conditions.


Conclusion

Well, that just about wraps up our guide on how accurate the ECG is on your AppleWatch. We hope this could be of some help to you.

If you need help interpreting your Apple Watch ECGs, don't worry, we understand how scary and confusing it can be to experience irregular heartbeats. That's why we created the Qalyapp for you and for the hundreds of millions of people around the world who live with heart palpitations and abnormal heart rhythms. On the Qalyapp, human experts will interpret your Apple Watch ECGs within minutes for clarity and peace of mind.

To get started with the Qalyapp, grab the Qalyapp from the App Store or Play Store today. If you have any more questions, or if you need our help in any other way, don't hesitate to reach out to us at support@qaly.co.

As always from the team at Qaly, stay heart healthy ❤️

How Accurate the ECG Is on Your Apple Watch | Qaly (2024)

FAQs

How Accurate the ECG Is on Your Apple Watch | Qaly? ›

The sensitivity of Apple Watch's automated interpretation to detect an AF was 99.54%, while the manual interpretation yielded a sensitivity of 100%. Conclusion The results of this study demonstrated a robust relationship between the 12-lead ECG and Apple Watch ECG in the diagnosis of arrhythmias.

How reliable is an Apple Watch ECG? ›

Key Takeaways. In short, the Apple Watch ECG is very accurate. One study by a Stanford Asociate Professor of Medicine demonstrated that the Apple Watch could accurately detect AFib in 84% of cases when compared to a traditional 12-lead ECG.

Can an Apple Watch detect an irregular heartbeat? ›

On Apple Watch Series 1 or later, the IRNF analyzes pulse rate data collected by the photoplethysmograph (PPG) sensor to identify episodes of irregular heart rhythms suggestive of AFib, and it provides a notification to the user when it detects an episode.

Is ECG trustworthy? ›

Most heart doctors consider an ECG as a basic tool to screen for heart disease, although its use needs to be individualized. If symptoms tend to come and go, a regular ECG may not find a change in the heartbeat. Your healthcare team may suggest wearing an ECG monitor at home.

What results can you get on Apple Watch ECG? ›

The Apple Watch ECG app can provide four possible results – Sinus Rhythm (regular heart pattern), Atrial Fibrillation (irregular rhythm), Low Heart Rate or High Heart Rate (if your heart rate is below 50 BPM or above 120 BPM on ECG version 1, or above 150 BPM on ECG version 2), and Inconclusive (if the app can't ...

Is the Apple Watch ECG FDA approved? ›

In a clinical study using a 12-lead ECG as a reference device, the ECG app demonstrated 99.3% specificity in classifying sinus rhythm and 98.5% sensitivity in classifying AFib for the classifiable results. The ECG app received 510(k) clearance from the FDA for users 22 years and older.

What does AFib look like on ECG? ›

In comparison with Sinus rhythm, AF has no P wave as the SA node is not functioning. However, the atria generate up to 600 stimuli/min and each stimuli is picked up by the ECG machine. So, instead of a P wave, what you see is a number of small waves of differing sizes known as fibrillatory "F" waves.

Should I be worried about an inconclusive ECG on my Apple Watch? ›

If you're still seeing an Apple Watch Inconclusive ECG after taking steps to prevent your Apple Watch from labeling your ECG Inconclusive, it may be a sign of an underlying heart abnormality like an SVT ECG or a Short PR Interval.

Does Apple Watch ECG only check for AFib? ›

Apple Watch only checks for signs of atrial fibrillation periodically. AFib History may not find every instance of your irregular rhythm.

What does AFib look like on an Apple Watch? ›

To recognize Afib on your watch ECG, look for an irregularly irregular rhythm with fibrillatory waves instead of visible P waves.

Can anxiety cause abnormal EKG? ›

In some patients with traits of anxiety the electrocardiogram may show RS-T segment deviations and low or diphasic T waves in various leads. Reassurance of the patient and fifteen minutes of rest before repetition of the test the next day are often followed by a complete reversal of such changes.

Can ECG detect heart blockage? ›

An ECG is a great test to analyse heart signals and can directly or indirectly help spot heart blockages or artery issues.

What is more accurate ECG or EKG? ›

The question of whether EKG and ECG are the same test often arises due to the usage of different abbreviations in different regions or countries. The confusion stems from the fact that both terms refer to the same procedure, which is the recording and analysis of the heart's electrical activity.

What smartwatch do cardiologists recommend? ›

Top 3 features of best smartwatches for heart patients for you
Best smartwatch for heart patientsDisplay
Noise Newly Launched Endeavour Smart Watch1.46 inch AMOLED Always On
Apple Watch SE (2nd Gen) [GPS 40 mm]1.78 inches
Fastrack Reflex Play Smart Watch1.3 inch AMOLED
Apple Watch Series 91.7 inches
6 more rows
Jan 4, 2024

What is the difference between an EKG and an ECG? ›

EKG and ECG are actually different spellings of the same diagnostic test that monitors your heart's electrical activity. EKG is the abbreviation from the German spelling of electrocardiogram (which is elektrokardiogramm in German). The EKG abbreviation came into use because of where the test was initially invented.

What finger do you use for Apple Watch ECG? ›

Apple Watch's Electrocardiographic Function

In this simple procedure, the watch is worn on the left wrist, and the wearer launches the ECG application on the watch and touches the digital crown of the watch with a right-hand finger.

How reliable is the Apple Watch heart rate? ›

Even under ideal conditions, Apple Watch may not be able to get a reliable heart rate reading every time for everybody. And for a small percentage of users, various factors may make it impossible to get any heart rate reading at all.

How accurate is the Apple Watch heart rate? ›

Patients were randomly assigned two of the three devices, which they wore on each wrist, and readings were recorded at a baseline and during elevated PSVT episodes. After the study, researchers found that both the Apple Watch Series 2 and Samsung Galaxy Gear S3 achieved a 100% accurate heart rate within 10 bpm.

Is blood oxygen in an Apple Watch accurate? ›

The authors report 95% limits of agreement of -5.8% and +5.9%. In patients and conditions where the conventional pulse oximeter measured >90% spO2, the Apple Watch measured on average 1% higher than the conventional device.

Can Apple Watch detect sleep apnea? ›

The Takeaway. The new Apple Watch won't be able to diagnose sleep apnea.

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