A research report published in the Annals of Internal Medicine described a method to record a quasi-standard electrocardiogram (ECG) using the Apple Watch. When tested on patients, the standard limb leads obtained by the Apple Watch were comparable with those of a standard ECG.
The Apple Watch series 4 and 5 allow users to record an ECG by touching the device’s “digital crown” with a finger. The ECG then records 30 seconds of a “single channel ECG similar to a lead I ECG.” The Apple Watch ECG method monitors electrical activity in the direction of lead I. In the study, leads II and III were obtained by moving the Apple Watch to the ankle or leg and touching the digital crown with a finger on the right hand (lead II) or left hand (lead III). The leads obtained using this method were comparable to those obtained with conventional electrocardiography in both a healthy patient and a patient with ST-segment elevation myocardial infarction. Additionally, precordial leads could be approximated by placing the back of the Apple Watch to the chest and touching the digital crown with the right finger. In this way, a chest-right arm lead was formed between the right arm and the precordium. The chest-right arm leads obtained with this method were similar to leads V1 and V6 in a traditional ECG.
These data support the feasibility of recording an ECG with the Apple Watch. According to the authors, the process is relatively simple and can be performed independently, allowing users to self-record ECGs. “The availability of a method to record an ECG with diagnostic potential anytime and anywhere could potentially revolutionize our approach to cardiac emergencies,” primary author Dr Cobos Gil wrote. However, further studies are necessary to validate this methodology and assess its efficacy in patients with suspected or confirmed heart disease.
Cobos Gil MÁ. Standard and precordial leads obtained with an Apple Watch [published online November 26, 2019]. Ann Intern Med. doi:10.7326/M19-2018