Lab test · Cardiovascular
Electrocardiogram (ECG)
An ECG records the heart's electrical activity. What a clinical ECG shows, how it differs from a smartwatch ECG, and when it is used.
Written by LON6EVITY Editorial Team · Last updated
What it measures
MedlinePlus explains that an ECG records the electrical signals of the heart using electrodes on the skin, showing heart rate, rhythm and signs of problems such as a previous heart attack or an enlarged heart.
When it is used
NHLBI lists the ECG among common heart tests used to look for heart rhythm problems and heart disease, often in people with symptoms such as chest pain or palpitations.
Clinical vs smartwatch ECG
A standard clinical ECG uses 12 leads. Some smartwatches offer a single-lead ECG that can check for atrial fibrillation but cannot detect a heart attack or many other conditions.
Factors that can affect the result
- Symptoms
- Medicines
- Electrolyte levels
- Electrode placement
Questions people commonly ask
- Can a smartwatch replace an ECG?
- No. A single-lead watch ECG is useful for rhythm checks but is not a substitute for a clinical 12-lead ECG.
Related topics
Keep your health results in one place
What does this mean for your own health data? Log your results, follow trends over time and bring an organised summary to your next doctor's appointment.
Sources
- Electrocardiogram. MedlinePlus, U.S. National Library of Medicine.
- Heart Tests. National Heart, Lung, and Blood Institute (NIH).