Fitbit ECG App Instructions for Use

Table of Contents

Introduction

This document provides instructions for using the Fitbit ECG app. The app is designed to record, analyze, and display a single-lead electrocardiogram (ECG) similar to a lead I ECG. It helps identify signs of atrial fibrillation (AFib) or normal sinus rhythm.

Product Description

The Fitbit ECG app is a software-based mobile health application that works with compatible Fitbit wrist-worn devices. It generates, records, stores, transfers, and displays a single-lead ECG. The app can classify heart rhythm as either normal sinus rhythm or atrial fibrillation. It is not intended for diagnostic purposes but provides results that can aid in discussions with a healthcare provider. ECG data can be used for non-clinical purposes, such as heart rate calculation. ECG recordings are temporarily stored on the wrist-worn device until synchronized with your Fitbit account, after which they can be viewed in the Fitbit app on your phone or tablet.

ECG data is found in the Heart Rhythm Assessment tile within the Assess & Report section of the Fitbit app. This tile also facilitates onboarding, viewing past results, exporting reports, and accessing device information.

Precautions

This function has not been tested and is not intended for use by individuals under 22 years of age or those with pacemakers, implantable defibrillators, or other implanted cardiac devices.

Do not change your medications without first consulting your doctor. The Fitbit ECG app results may not be accurate for individuals using medications or substances that affect heart rate or circulation.

Do not use this product as a substitute for physician-prescribed treatment. Symptoms of atrial fibrillation can include palpitations and shortness of breath, though some individuals may have no symptoms. Atrial fibrillation is treatable, and early detection can lead to timely management by you and your doctor.

If you experience symptoms suggestive of atrial fibrillation or have other concerns, speak with your doctor. Device or user error can lead to false positive or false negative results. A false negative result may delay seeking medical attention, potentially leading to prolonged atrial fibrillation. A false positive result may lead to unnecessary further testing or inappropriate changes to lifestyle or habits.

Do not use for clinical diagnosis of atrial fibrillation.

Do not use for continuous or real-time monitoring of heart rhythm.

This product cannot detect heart attack, blood clots, stroke, or other heart conditions.

The assessment performed by this product is NOT a diagnosis.

This product has NOT been tested on pregnant women.

This product is NOT INTENDED for use in a clinical setting.

Without consulting a qualified healthcare professional, DO NOT attempt to interpret the assessment results or self-treat based on them.

DO NOT perform ECG measurements when the Fitbit wrist-worn device is outside the operating temperature or humidity range specified in the device's user manual. DO NOT measure underwater.

Atrial fibrillation may not cause the heart to beat irregularly constantly, making it difficult to detect even during a doctor's visit.

Wear your Fitbit wrist-worn device as instructed. NOTE: The Fitbit ECG app can only be used on compatible Fitbit wrist-worn devices paired with an account. For information on Fitbit wrist-worn devices compatible with the Fitbit ECG app, visit help.fitbit.com.

For security reasons, it is recommended to safeguard your compatible wrist-worn and mobile devices to prevent unauthorized access to your health data. Refer to your mobile device manufacturer's instructions for enabling passcode protection. Secure your Fitbit account with a strong password. For more information, visit help.fitbit.com. If your wrist-worn device has a lock feature, enable it. For more information, visit help.fitbit.com.

If you believe this product violates any law or endangers any person, report it to the manufacturer and the local public health authority.

How the Fitbit ECG App Works

The electronic sensors on your Fitbit wrist-worn device detect your heart rhythm. The captured data is analyzed to identify signs of atrial fibrillation or irregular heart rhythm. The sensors are located on the back of the device, either on the metal frame around the display (Fitbit Charge 5, Fitbit Sense, and Fitbit Sense 2) or on the side button (Google Pixel Watch). When these sensors are in contact with your skin and the Fitbit ECG app is open, they record electrical signals from your heart.

Normally, the upper and lower chambers of the heart contract simultaneously. In atrial fibrillation, the upper chambers contract irregularly, increasing the risk of heart attack, blood clots, stroke, and other heart conditions.

Atrial fibrillation may not cause the heart to beat irregularly constantly, making it difficult to detect. While this assessment cannot diagnose atrial fibrillation, you can initiate it from your wrist. The results can help you have a more productive conversation with your doctor.

Results You May See

• Normal Sinus Rhythm: Your heart rhythm appears normal. It does not show signs of atrial fibrillation or irregular heart rhythm. Tap "Learn More" for more details and "Done" to finish the assessment.
• Atrial Fibrillation: Your heart rhythm shows signs of atrial fibrillation or irregular heart rhythm. Atrial fibrillation can have serious health consequences. You should consult your doctor. Tap "Learn More" for more details and "Done" to finish the assessment.
• Inconclusive: Your heart rate was too high (over 120 bpm) or too low (under 50 bpm), and the Fitbit ECG app could not assess your rhythm. An inconclusive result may have several possible causes, including excessive movement during the measurement, not resting your hands on a table, or another arrhythmia. For more information, see the "Troubleshooting" section on page 13.

Operating Instructions

Installing the Fitbit ECG App

If the Fitbit ECG app is not yet installed on your Fitbit wrist-worn device, download it.

Fitbit Charge 5, Fitbit Sense, and Fitbit Sense 2

1. Keep your device nearby. On the Today tab in the Fitbit app, tap the icon in the upper-left corner to view your device's image.
2. Tap the Gallery tab, then Apps.
3. In the list of apps, tap ECG, then Install.

Google Pixel Watch

1. Search for the Fitbit ECG app in the Play Store on your watch or phone. If you are using the Play Store on your phone, ensure your device is set to Google Pixel Watch.
2. Tap the Fitbit ECG app, then Install.
3. Open the Fitbit ECG app on your watch. If you do not have the Fitbit app installed on your phone, you will be prompted to install it. Follow the prompts and sign in to the Fitbit app on your phone.

For more information about the availability of the Fitbit ECG app in your region, visit fitbit.com/ecg.

The Fitbit ECG app can only be used on compatible Fitbit wrist-worn devices paired with an account. Currently, the Fitbit ECG app is available on Fitbit Sense (with Fitbit OS 5.0 or later), Fitbit Sense 2, Fitbit Charge 5 (with firmware CU 1.2 or later), and Google Pixel Watch. For more information, visit help.fitbit.com.

Performing an Assessment

Before taking your first measurement, review the introduction to heart rhythm assessment:

1. Open the Fitbit app on your phone or tablet and sign in to your Fitbit account if you have not already done so.
2. On the Explore tab in the Fitbit app, tap Assess & Report > Heart Rhythm Assessment, and follow the instructions. After reviewing the introduction to Heart Rhythm Assessment, you can take an ECG measurement.

ECG Measurement Procedure:

1. Wear your Fitbit wrist-worn device snugly but comfortably. It should be positioned about a finger's width above your wrist bone. For more information, visit help.fitbit.com.
2. Sit down and open the ECG app on your wrist-worn device.
3. Follow the on-screen instructions on your Fitbit wrist-worn device to start the assessment.
4. Place your finger(s) on the Fitbit wrist-worn device as shown on the screen. Keep your finger(s) on the contact point(s) until the countdown is complete.
5. Once the results are displayed, swipe up to view the full report. Remember, your Google Pixel Watch must be connected to LTE or Wi-Fi for ECG data to sync with the Fitbit app.

Canceling an Assessment

You can cancel an assessment at any time by pressing the button on a Fitbit Sense or Fitbit Sense 2, pressing the side button on a Google Pixel Watch, or swiping right on a Fitbit Charge 5. You will only get a result if a 30-second ECG measurement and data analysis are completed. If you cancel the assessment before it is finished, you will not get a result.

Viewing Results

After completing the heart rhythm assessment and data analysis, you will see one of the following results:

• Normal Sinus Rhythm: Your heart rhythm appears normal. Tap "Learn More" for more details and "Done" to finish the assessment.
• Atrial Fibrillation: Your heart rhythm shows signs of atrial fibrillation. You should consult your doctor. Tap "Learn More" for more details and "Done" to finish the assessment.
• Inconclusive: Your heart rate was too low or too high, or the ECG app could not measure correctly. Tap "Try Again" to repeat the measurement, or "Done" to finish the assessment. For more information on why you received this result, see "Troubleshooting" on page 13.

After opening the Fitbit app, your results are sent from your Fitbit wrist-worn device to the Fitbit app and can then be viewed on your phone or tablet. Remember, your Google Pixel Watch must be connected to LTE or Wi-Fi for ECG data to sync with the Fitbit app. Later, for example, during a consultation with your doctor, you can view your results by following these steps:

1. On the Explore tab in the Fitbit app, tap Assess & Report > Heart Rhythm Assessment.
2. Tap "View Results" to see a list of all previous results.
3. Tap the desired results to view detailed information. Results always include the date and time they were recorded using a compatible Fitbit wrist-worn device. For each result, you can tap "Export PDF for Doctor" to download a report. When ready, you will receive a notification. It is recommended to use the latest version of Adobe Acrobat Reader to open the report.

For more information about heart rhythm assessment, visit help.fitbit.com.

Removing Results

1. On the Explore tab in the Fitbit app, tap Assess & Report > Heart Rhythm Assessment.
2. Tap "View Results" to see a list of all previous results.
3. Tap the results you want to remove.

Uninstalling and Reinstalling the Fitbit ECG App

To remove the Fitbit ECG app:

Fitbit Charge 5, Fitbit Sense, and Fitbit Sense 2

1. On the Today tab in the Fitbit app, tap the icon in the upper-left corner to view your device's image.
2. Tap Gallery.
3. In the list of apps installed on your watch, find the ECG app and tap it.
4. Tap Uninstall.

Google Pixel Watch

1. Open the Play Store on your watch.
2. Tap My Apps.
3. In the list of apps installed on your watch, find the Fitbit ECG app and tap it.
4. Tap Uninstall.

You can reinstall the app at any time from the Fitbit gallery. For more information on removing, installing, and managing apps, visit help.fitbit.com.

Troubleshooting

There are three types of inconclusive results you may see after an assessment:

Inconclusive: High Heart Rate

If your heart rate is higher than 120 bpm, the Fitbit ECG app cannot assess your heart rhythm. Your heart rate may be high for many reasons, including:

• Recent exercise
• Stress
• Nervousness
• Alcohol
• Dehydration
• Infection
• Atrial fibrillation or another arrhythmia

For more information, consult the American Heart Association or visit the European Society of Cardiology website [https://www.escardio.org/].

Inconclusive: Low Heart Rate

If your heart rate is lower than 50 bpm, the Fitbit ECG app cannot assess your heart rhythm. Low heart rate can be due to various reasons, including:

• Taking certain medications, such as beta-blockers or calcium channel blockers.
• Being in peak aerobic condition from exercise.
• Another arrhythmia.

For more information, consult the American Heart Association or visit the European Society of Cardiology website [https://www.escardio.org/].

Inconclusive: Measurement Not Successful

An inconclusive result may have several possible causes. The most common include:

• Moving too much during the measurement.
• Not resting your hands on a table.
• Another arrhythmia.

If your Fitbit ECG app measurement was not successful, try the following tips:

• You must be seated and relaxed.
• During the assessment, rest your arms on a table and do not move.
• Ensure your Fitbit wrist-worn device is positioned on your wrist as selected during the initial setup.
• Keep your finger(s) on the Fitbit wrist-worn device throughout the assessment.
• Check how your Fitbit wrist-worn device fits. It should be snug but comfortable, not too tight. It should be positioned about a finger's width above your wrist bone. For more information, visit help.fitbit.com.
• Ensure there is no interference with the electrode contact (hair, jewelry, clothing, etc.).
• Avoid being near other electronic devices that could cause interference.
• Ensure your Fitbit wrist-worn device and wrist are clean and dry. Water or sweat can interfere with measurements. If you have just washed your hands, splashed, showered, or sweated, clean and dry the wrist-worn device. For wearing and care instructions, visit fitbit.com/productcare.
• Try again and repeat the assessment. If you repeatedly get an inconclusive result or feel unwell, consult your doctor.

For troubleshooting synchronization issues, visit help.fitbit.com. For troubleshooting heart rate tracking, visit help.fitbit.com.

Clinical Study

The purpose of the clinical study was to verify that the Fitbit ECG app's software algorithm could classify heart rhythm as either atrial fibrillation (AFib) or sinus rhythm (SR) from an ECG waveform corresponding to lead I ECG, and to confirm that this software could generate a waveform similar to lead I from a 12-lead ECG.

A total of 472 subjects were enrolled in the study across 9 US sites. Some of these subjects had been previously diagnosed with atrial fibrillation. Eligible subjects underwent a 10-second 12-lead ECG recording. Subjects with a known history of AFib were examined by a qualified physician to confirm AFib and were assigned to the AFib cohort. Subjects without a known AFib history had their SR checked and were assigned to the SR cohort.

440 subjects subsequently underwent a 30-second 12-lead ECG recording and a simultaneous Fitbit ECG app measurement. The Fitbit ECG app's software algorithm correctly identified individuals with AFib in 98.7% of cases and individuals with SR in 100% of cases.

In a qualitative comparison, when the 12-lead ECG and Fitbit ECG app waveforms were visually compared for AFib and SR classification, the single-lead waveform from the Fitbit ECG app was considered similar to lead I of a 12-lead ECG in 95% of cases.

In a quantitative comparison, when R-wave amplitudes between the 12-lead ECG and the Fitbit ECG app were compared, the Fitbit ECG app's R-wave amplitudes were, on average, 2.4 mm larger than the reference R-wave peaks of the 12-lead ECG. This is attributed to the placement of the 12-lead ECG on the subject's torso, rather than the wrist, as was the case in the clinical study.

No adverse effects were observed during the clinical study.

About Conditions and Self-Care

What is Atrial Fibrillation?

Atrial fibrillation (AFib) is a type of irregular heart rhythm of the upper heart chambers (atria). Normally, the atria contract regularly, moving blood into the lower chambers. In AFib, the atria contract irregularly, causing blood to flow more slowly through the atria. This slower-flowing blood can form clots, increasing the risk of stroke and heart problems.

Signs You May Have Atrial Fibrillation

Some people with atrial fibrillation show no signs of the condition, while others may experience the following symptoms:

• Irregular heartbeat
• Palpitations
• Dizziness
• Extreme fatigue
• Shortness of breath
• Chest pain

For more information, consult the Centers for Disease Control and Prevention (CDC) or visit the European Society of Cardiology website [https://www.escardio.org/].

Lifestyle and Other Factors

Risk factors for AFib include:

• Advanced age
• High blood pressure
• Obesity
• European ancestry
• Diabetes
• Heart failure
• Coronary artery disease
• Hyperthyroidism
• Chronic kidney disease
• High alcohol consumption
• Enlargement of the left ventricle of the heart

For more information, consult the Centers for Disease Control and Prevention (CDC) or visit the European Society of Cardiology website [https://www.escardio.org/].

Possible Treatments

Before making any significant lifestyle or medication changes, consult your doctor. Possible treatments include:

• Medications
• Surgery
• Lifestyle changes

For more information, consult the Centers for Disease Control and Prevention (CDC) or visit the European Society of Cardiology website [https://www.escardio.org/].

Information for Doctors

A guide for doctors is available. Visit help.fitbit.com or call (877) 623 4997.

Terms of Service

Fitbit designs products and tools to help you achieve your health and fitness goals, enabling you to live a healthier and more active life and inspiring you to do so. These Terms of Service (the "Terms") govern your access to and use of the Fitbit service. "Fitbit service" means our devices, including associated firmware, applications, software, websites, APIs, products, and services.

If you live in the European Economic Area, the United Kingdom, or Switzerland, these Terms are an agreement between you and Fitbit International Limited, an Irish company with its registered office at 76 Lower Baggot Street, Dublin 2, Ireland. If you live elsewhere, these Terms are an agreement between you and Fitbit LLC, 199 Fremont Street, 14th Floor, San Francisco, CA 94105, USA. The terms "Fitbit," "we," "us," or "our" refer to the party to the agreement that provides you with the Fitbit service.

To create a Fitbit account and access or use the Fitbit service, you must accept these Terms. If you do not have an account, you accept these Terms by using any part of the Fitbit service. If you do not accept these Terms, do not create an account and do not use the Fitbit service.

For more information on these terms, see the Fitbit Terms of Service.

User Information

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