Apple released the ECG feature of the Apple Watch Series 4 in Germany on March 27, 2019. From all models of the Smartwatch, you can now also refer to atrial fibrillation. This makes the tech gadget a medical device.

With the ability to create an electrocardiogram, the Apple Watch is no longer just a smartwatch or a fitness wearable, but is also becoming a medical device. For Apple has built in the Apple Watch Series 4 in addition to the optical and an electric heart sensor. The older models can only measure the pulse with their optical sensor, but can not create an ECG.

Electrocardiogram: ECG only on the Apple Watch Series 4

To create an electrocardiogram using the Apple Watch Series 4, you must first enable the feature in the Heart section of the Health app. During activation, the app shows you what the ECG measures and what conclusions you can draw from it. These include the sinus rhythm, which indicates a flawless heart beating, but also the detection of atrial fibrillation. In addition, the app indicates a particularly high or low heart rate and in rare cases, the findings may also be indecisive – for example, if you move too much in the measurement. Just as important is the indication of what the ECG can not do, such as detecting a heart attack or stroke. And that in case of doubt you should always consult a doctor and never change a prescribed dose of medication without consulting with the doctor.

The ECG app will appear after activation on the home screen of the Apple Watch. Once it’s started, place your thumb on the crown of the watch to close the circuit and measure your heart for 30 seconds. After the measurement, the app displays its findings and you can add symptoms about your own well-being to capture the most complete picture possible. The data load directly from the smartwatch in the health app on the connected iPhone. Here is also an export to PDF format possible, which is mainly intended to present the results to a doctor.

In the US, the ECG feature of the Apple Watch Series 4 has been released since the fall of 2019. During this time, Apple has conducted a study with several medical institutions. The findings include, according to Apple, that in the detection of sinus rhythm, the accuracy was 99 percent and in atrial fibrillation with 98.3 percent only marginally behind it.

Messages about irregular heart rhythm

In addition to the ECG, Apple has also activated the detection of irregular heart rhythm, the most common form of which is so-called atrial fibrillation, in Germany. This feature is available on every Apple Watch. For them, the optical heart sensor is sufficient. But you also have to activate this yourself in the health app. Unlike the ECG, you can not actively execute the detection. Instead, the app continuously checks in the background the results of the pulse measurement of the Apple Watch at irregular intervals on abnormalities. So while it does not recognize any disorder, the more frequently a cardiac arrhythmia occurs, the more likely it will be detected.

If so, the Apple Watch will send you a message about the irregular heartbeat. In the Health-App you can see more data about it and start the walk to the doctor for a closer examination and possibly further treatment.

data protection

Like all other health data, Apple also stores heart rate measurements and ECG results in the health app on the iPhone. There they are encrypted, as long as the smartphone is locked. The data only reaches the servers of Apple, if you put a backup in the iCloud, but are still encrypted. This will be necessary at the latest if you want to move the data to a new iPhone.