Electrocardiogram

Quick assessment of heart rhythm and electrical activity to detect arrhythmias or other cardiac issues

Electrocardiogram

Table of contents

Basic data

An electrocardiogram (ECG or EKG) is a fast, non-invasive test that records the electrical signals in your heart. It’s used to identify irregular heart rhythms, structural abnormalities, and signs of past or impending heart problems.

It’s often the first-line test for evaluating cardiac symptoms such as chest pain, palpitations, dizziness, or fatigue — but it can also be part of a proactive cardiovascular health assessment.

Category: Cardiovascular tests

Level: Basic

Usefulness: Medium

Level

Basic

Recommended for individuals with cardiovascular risk factors or those experiencing symptoms such as palpitations, dizziness, or unexplained fatigue. May also be valuable as part of a baseline cardiac screening protocol for health-conscious individuals over 35.

Usefulness

Medium

While limited in scope compared to longer-term heart monitoring methods, a resting ECG can reveal critical information about your heart’s electrical function.
Detects arrhythmias

Identifies irregular heartbeat patterns such as atrial fibrillation or premature ventricular contractions (PVCs).

Reveals signs of heart stress

Can show signs of previous heart attacks, ischemia, or electrolyte imbalances impacting cardiac function.

How it works

Small electrodes are placed on the chest, arms, and legs. These pick up the electrical impulses of the heart and transmit them to the ECG machine.
Data collection

Electrical signals are recorded over ~10 seconds while you lie still in a resting position.

Interpretation

A cardiologist or trained technician analyzes the waveforms for abnormalities in rhythm, rate, and shape.

Measures

The ECG provides a snapshot of the heart’s electrical patterns.
Heart rhythm and rate

Identifies bradycardia, tachycardia, or irregular patterns like atrial fibrillation.

P wave, QRS complex, and QT interval

Measures specific parts of the heart’s electrical cycle that may indicate conduction abnormalities or risks.

Reliability

The resting ECG is reliable for capturing a moment-in-time electrical profile, but limited in its ability to detect transient issues.
Limited to resting state

Irregularities may go unnoticed if not present during the short recording.

Operator-dependent placement

Accuracy can be affected by improper electrode positioning or interference.

Limitations

The test only records about 10 seconds of heart activity and may miss intermittent problems.
Low sensitivity to rare arrhythmias

Intermittent electrical abnormalities might not appear during a brief snapshot.

Not a structural imaging tool

ECG does not provide anatomical visuals — it must be paired with echocardiography or imaging for full evaluation.

Frequency

Suggested cadence

Every 1–3 years if asymptomatic; more frequently if cardiovascular symptoms or risk factors are present.

Cost

Typical costs

Typically ranges from €20–€100, depending on country, provider, and whether it’s part of a broader cardiology consultation.

Availability

Where available

Widely available in clinics, hospitals, and cardiology offices. Increasingly accessible through mobile and wearable devices.

Preparation

How to prepare

No specific preparation needed. Avoid caffeine and stress before the test if possible, and wear clothes that allow access to your chest.

Interpretation

ECG waveforms are interpreted by a trained specialist who looks for abnormalities in rhythm, rate, and waveform shape.
Rhythm and rate analysis

Identifies signs of arrhythmia or conduction delay.

ST-segment and QT interval

Abnormal patterns may suggest ischemia, electrolyte imbalance, or medication side effects.

Alternatives

Holter Monitor

Offers longer-term heart rhythm tracking (typically 24–72 hours) to capture intermittent abnormalities.

Echocardiogram

Provides structural visualization of the heart and valves to complement the functional data from ECG.

FAQ

Is an ECG painful or invasive?

No — it’s completely non-invasive and painless. Electrodes are applied to the skin, and the test usually takes just a few minutes.

Can I use a smartwatch ECG instead?

Consumer wearables can help identify heart irregularities, but they’re not a substitute for a full 12-lead ECG reviewed by a clinician.