The Apple Watch 4 is able to record an electrocardiogram (ECG) directly on the wrist. So far the function was only activated in the USA. With the watchOS update to version 5.2, Apple releases the ECG app in other countries, including Germany. The ECG app and a message with irregular heart rhythm are now approved according to Apple in the European Economic Area and provided with the CE mark.
The ECG is recorded on the Apple Watch using electrodes on the back of the watch and in the crown. To close the circuit and perform the ECG, the user must place their finger on the crown for about 30 seconds. Accuracy was confirmed in a clinical study with around 600 participants, according to Apple. The records are available in the health app and can be exported to the doctor as a PDF.
The ECG of the Apple Watch 4 is a 1-channel recording that is less informative than a professional 12-lead ECG. This allows the ECG app to see if the user has a normal sinus rhythm or signs of atrial fibrillation. Health problems such as heart attack, blood clots, stroke, high blood pressure or heart failure, as well as other types of arrhythmia, cannot recognize the Apple Watch. In no case does she replace a doctor and a professional examination.
Regardless of the ECG function, older Apple Watch models can record the pulse. These now also have the function to alert the user to irregular heart rhythm. In return, the pulse is repeatedly measured in the background. A notification is made when five measurements taken over a period of at least 65 minutes reveal an irregular heart rhythm, which could be a sign of atrial fibrillation. This message aims to alert users to potential heart problems they are not yet aware of.