Smartwatches to Record ECGs for Diagnosis of ST-Segment Changes

Quick Takes

  • Wearable devices such as smartwatches can record ECG tracings; when the watch is placed on the chest, they are comparable to standard ECG recordings.
  • Smartwatches hold promise for detecting ECG changes when an ACS event is suspected.

Study Questions:

Can electrocardiographic (ECG) recordings from a smartwatch accurately detect ST-segment changes associated with acute coronary syndromes (ACS)?


A total of 100 participants were provided with a commercially available smartwatch to record multiple-channel ECGs. Fifty-four patients with ST-elevation myocardial infarction (STEMI), 27 patients with non-STEMI elevation myocardial infarction (NSTEMI), and 19 healthy adults were included in the study. The study was conducted from April 19, 2019, to January 23, 2020. The watch was placed in different body positions to obtain nine bipolar ECG tracings (corresponding to Einthoven leads I, II, and III and precordial leads V1-V6) that were compared with a simultaneous standard 12-lead ECG. The primary outcome of interest was concordance between ECG recordings from the smartwatch and standard 12-lead ECGs.


One hundred participants were enrolled in the present study, of which 67 were men (67%), and the mean (standard deviation [SD]) age was 61 (16) years. The smartwatch tracings and standard ECGs were comparable for the identification of a normal ECG (Cohen κ coefficient, 0.90; 95% confidence interval [CI], 0.78-1.00) and ST-segment elevation changes (Cohen κ coefficient, 0.88; 95% CI, 0.78-0.97). The smartwatch ECG was also comparable to standard ECGs for non–ST-segment elevation changes (Cohen κ coefficient, 0.85; 95% CI, 0.74-0.96). Agreement between the smartwatch and standard ECG was also noted in the ability to detect the amplitude of ST-segment changes (bias, −0.003; SD, 0.18; lower limit, −0.36; and upper limit, 0.36). The use of the smartwatch ECG for the diagnosis of normal ECG showed a sensitivity of 84% (95% CI, 60%-97%) and specificity of 100% (95% CI, 95%-100%). For ST elevation, the sensitivity was 93% (95% CI, 82%-99%), and the specificity was 95% (95% CI, 85%-99%). For NSTE ECG alterations, the sensitivity was 94% (95% CI, 81%-99%), and the specificity was 92% (95% CI, 83%-97%).


The authors concluded that the findings of this study suggest agreement between the multichannel smartwatch ECG and standard ECG for the identification of ST-segment changes in patients with ACS.


The use of commercially available smartwatches to record ECGs demonstrates promise for the detection of abnormalities in ECG tracings when no standard ECG recording devices are available. However, many adults at risk for ACS may not be able to afford smartwatches or live in rural areas where connectivity to the internet may reduce the ability for cardiovascular providers to review these tracings. In addition, as noted in the report, difficulties in placing the smartwatch in the proper locations were reduced for participants with tremors or stroke. Additional research to evaluate the acceptability and feasibility of using such devices is warranted.

Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Prevention, Stable Ischemic Heart Disease, Vascular Medicine, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Chronic Angina

Keywords: ESC Congress, ESC20, Acute Coronary Syndrome, Arrhythmias, Cardiac, Electrocardiography, Internet, Myocardial Infarction, ST Elevation Myocardial Infarction, Stroke, Primary Prevention, Tremor

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