How to Do an ECG on an Apple Watch?

Medical features in devices like watches have helped us make a shift in healthcare accessibility. Individuals can conveniently and effectively monitor their heart health. It thus supports improved health outcomes through timely interventions.

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Incorporating ECG features on the Apple Watch represents an advancement in personalized healthcare monitoring. It allows users to take an ECG directly from their Apple Watch, and the Apple Health app enables users to capture the heart rhythm simply by placing a finger on the digital crown. It completes the circuit that measures electrical signals from the heart to provide data.

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Atrial fibrillation (Afib) is a common irregular heartbeat condition that ECG detects. Stroke is a complication of Afib, so its early detection is important. The Apple Watch ECG app identifies AFib and secures ECG data on the iPhone. This blog will help us learn how to take an ECG with the Apple Watch.

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What is an Apple Watch?

Making phone calls, sending text messages, and reading emails are not the only functions of Apple smartwatches. Initially, they were designed to complement phones. The Apple Watch is popular for its innovation, fitness tracking, health monitoring, and ability to use the Internet of Things (IOT). Now, it can measure blood oxygen, ECG readings, and body temperature. The watch is synced with the user's iPhone.

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How do Apple Watches work?

Photoplethysmography (PPG) is a simple and easy method that helps to detect blood flow in the body. It involves placing a small sensor on the skin, as in fingertip pulse oximeters. The technique is based on the optical properties of human body composition under a specific wavelength of light. The properties are

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• Absorption.

• Scattering.

• Transmission.

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Every heartbeat creates a volume change, which the sensors detect. The PPG signals include rapid fluctuations corresponding to heartbeats and also slow changes influenced by breathing, thermoregulation, and autonomic nervous system activity.

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• heart rate.

• oxygen level.

• blood pressure and how well your blood vessels work. 

• Vascular health, such as pulse wave velocity and heart rate variability.

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It has become popular because the technology is cheap and easy to use, even at home. 

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The working mechanism of the Apple Watch 

Blood reflects red light and absorbs green light. The Apple Watch uses green LED lights and light-sensitive photodiodes to detect blood flow. More blood flows during the heartbeats, increasing the green light absorption between the beats; less light is absorbed between heartbeats when the volume is low. Apple Watch calculates the number of times the heart beats in a minute, hence the heart rate.

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The optical heart sensor supports a range of 30 to over 200 beats/minute, depending on the activity. If the signal is weak, it increases LED brightness. The Apple Watch uses infrared light in the background for heart rate notifications. Green LED lights are used during workouts and breathing sessions. Depending on the model, Heart Rate Variability (HRV) is calculated using both optical and electric sensors.

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How to use the Apple Watch ECG app?

1. Before starting, ensure the ECG app is available in your country or region.

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2. Update your iPhone to the latest version of iOS and your Apple Watch to the latest version of Watch OS.

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3. The ECG app is intended for users above the age of 22 years.

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Install and set up the ECG app:-

Open the health app on the phone, follow the on-screen steps, and set up the ECG app. After the complete setup, open the ECG app and take an ECG. If no prompts are visible, tap on the browse tab, select heart, and then ECG. Complete the setup by registering all personal information, such as date of birth, and confirm age eligibility.

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Once set up, check that the ECG app is installed on your watch, and navigate the watch app on your iPhone. If no app is visible on the Apple Watch, open the watch app on your iPhone, tap the heart in the ECG section, and select Install to get the ECG app. You can take an ECG whenever you experience a rapid or skipped heartbeat.

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Follow the step-by-step instructions:-

• See that the Apple Watch fits snugly on the wrist.

• Open the Apple Watch app.

• Tap the My Watch tab, General, and then Watch Orientation.

• Open the ECG app on the Apple Watch.

• Rest your arms on a table or in your lap.

• With the opposite hand, hold the finger on the digital crown; you need not apply any pressure.

• The recording takes 30 seconds. At the end, you receive a notification and can add the symptoms that appeared. 

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How to read results?

Once the ECG is done, you may receive any of the following kinds of results.

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1. Sinus rhythm

It means that the heartbeats are uniform and that the heart rate is between 50 and 100 beats per minute(bpm). It occurs when the upper and lower chambers of the heart beat in a coordinated manner. A sinus rhythm ECG implies that the particular recording always has a consistent pattern.

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2. Atrial fibrillation

An Afib result means the heart is beating in an irregular pattern. Afib is the most common form of serious arrhythmia or irregular heart rhythm. You should consult your doctor upon receiving a notification of Afib. The ECG app version 1 can check for Afib between 50 and 120 bpm, while the ECG app version 2 can check for Afib between 50 and 150 bpm.

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3. Low or high heart rate

1. A heart rate under 50 bpm or over 120 bpm in ECG version 1 affects the ECG app’s ability to check for Afib.

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2. In ECG version 2, heart rates below 50 bpm or above 150 bpm affect the ECG app's ability to detect Afib.

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4. Poor recording

It is unique to version 2. While recording the ECG, we must pay attention to the following:-

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• Rest our arms on the table while recording and should not move.

• The watch should fit snugly on the wrist. The back of the Apple Watch should be touching the wrist.

• Your wrist and Apple Watch should be clean and dry; water and sweat contribute to poor recordings.

• Ensure that you wear the Apple Watch on the wrist you selected in settings.

• View and share your health information.

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Open the Health app on your iPhone

On the iPhone tab, browse

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• Tap Heart.

• Tap ECG.

• Tap the chart for your ECG.

• Tap export a PDF for your ECG.

• Tap share/print.

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How to achieve the best results?

To achieve the best results, take the following precautions.

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• Place your arms fixed on the table, try to relax, but do not move.

• The Apple Watch should not be worn loose on the wrist. It should fit snugly.

• The wrist area should be clean and dry.

• To check, the Apple Watch must be worn on the wrist you selected in the Apple Watch app. Open the Apple Watch app, tap the My Watch tab, go to General, and then to Watch Orientation.

• Move away from all electronic items as they cause electrical interference.

• For a small percentage of people, the abnormal position of the heart in the chest can change the electrical signal levels and impact the ECG app’s ability to measure.

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Limitations of the Apple Watch:-

1. The ECG app cannot detect a heart attack if any chest pain, pressure, or tightness is experienced; you must consult emergency services.

2. It cannot detect a blood clot or a stroke.

3. It does not detect heart-related conditions like.

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• blood pressure, 

• congestive heart failure, 

• high cholesterol

• Arrhythmia (only Afib)

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Conclusion

The future of wearable technology provides significant advancements in heart health monitoring, providing individuals and healthcare professionals with real-time, continuous data. Innovations such as multi-lead sensors, artificial intelligence, and accuracy result in early detection and diagnosis of cardiovascular conditions.

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As wearable ECG technology becomes more affordable and reliable, it will revolutionize preventive healthcare and personalised care. It will be more advantageous for better disease management and improved health outcomes globally. Gauze is a participant in this revolution, bringing new technologies for assistance.