Short answer: An electrocardiogram (ECG or EKG) records the electrical activity of the heart through small electrodes on the chest, arms and legs. It takes a few minutes, does not hurt, and produces a strip of waves plus, usually, a printed summary with the heart rate, the rhythm and a few measured intervals. Doctors use it to look at rhythm, conduction and signs of strain or damage.
At a glance
| What it is | A few minutes' recording of the heart's electrical activity through electrodes |
|---|---|
| On the report | Heart rate, rhythm, PR, QRS and QT intervals, axis, and a conclusion |
| Normal rate at rest | About 60 to 100 beats per minute for adults |
| Common words | Sinus rhythm, bradycardia, tachycardia, block, ST changes |
| Keeping it | The PDF and the strip with the date, next to the symptoms you had |
| Watch ECG | A single lead; useful for rhythm, not the same test |
How it is done
You lie down with your chest uncovered; 10 sticky electrodes are placed (a "12-lead" ECG looks at the heart from 12 directions). You stay still for about 10 seconds while the machine records. Smartwatches record a single-lead ECG, which can show some rhythm problems but not everything a 12-lead ECG shows.
What the report contains
| On the report | Unit | What it describes |
|---|---|---|
| Heart rate | beats per minute (bpm) | how fast the heart beats during the recording |
| Rhythm (e.g. sinus rhythm) | — | where each beat starts; "sinus" means the normal pacemaker of the heart |
| PR interval | milliseconds (ms) | time for the signal to travel from the upper to the lower chambers |
| QRS duration | ms | time for the lower chambers to be activated |
| QT / QTc | ms | time for activation and recovery; QTc is corrected for heart rate |
| Axis | degrees | the main direction of the electrical activity |
The automated text printed by the machine (for example "abnormal ECG") is a computer suggestion and is often over-cautious; the doctor's reading is what counts. An old ECG is very useful for comparison, which is why it is worth keeping every one.
Keeping the report in your record
In Anpheros Daily you photograph the report or upload the PDF, and it goes into Documents under the person it belongs to, linked to the appointment it came from, next to the referral and the doctor's letter. On the Plus and Max plans "Read with AI" gives a plain-language summary and explains the terms, with the sentence each explanation came from marked; it stays labelled as AI, separate from what the specialist wrote. In the record the report is stored as an HL7 FHIR document, so you can share it with any doctor for a period you choose. Our guide on sharing your record with a clinic explains how.
What this page does not do
It explains what the investigation is and how its report is usually organised. It does not interpret your report or images, diagnose or recommend treatment. Reading the recording or images is the specialist's job; deciding what the report means for you is your doctor's.
Related pages
- Echocardiogram report explained
- Holter monitor (24-hour ECG)
- How accurate are smartwatch health measurements? Heart rate, SpO2, sleep and ECG
Sources
Frequently asked questions
What does "sinus rhythm" mean?
That the heartbeat starts in the sinus node, the heart's natural pacemaker. It is the normal starting point of the rhythm.
Is the computer interpretation on the ECG reliable?
It is a suggestion. Machines flag many things to be safe; a doctor reads the tracing and decides.
Can my smartwatch ECG replace a 12-lead ECG?
No. A watch records one lead and can detect some rhythm problems; a 12-lead ECG shows much more.
Why keep old ECGs?
Because a change from your previous ECG often tells a doctor more than one recording on its own.
Try it in Anpheros Daily
Keep your scan and test reports in one place in Anpheros Daily, ready to show at your next visit.
How it works in the app →
Anpheros builds a medical record that the patient controls and can share with any clinic, on an HL7 FHIR R4 platform, based in the EU. These guides help you understand and organise your health; they do not replace your doctor.
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