What is the electrocardiogram (ECG)?

By Cristiano Antonino On Mar 31, 2023

The electrocardiogram is an outpatient diagnostic test that allows the electrical activity of myocardial fibres to be recorded and graphically visualised

It is a practical, simple to perform, non-invasive method of assessing whether mechanical or electrical pathologies of the heart (e.g. heart attacks or rhythm disorders) are present.

This test can be performed at rest, while the patient is lying supine on the couch, or under stress, while the patient is walking on a treadmill or pedalling on an exercise bike.

What is the electrocardiogram for?

The electrocardiogram at rest makes it possible to diagnose the presence of arrhythmias (alterations in cardiac rhythm); ischaemia and/or infarction (cardiac suffering caused by a reduction in blood flow to the heart muscle due to narrowing of a coronary artery); acquired or congenital heart cavity alterations (e.g. valvulopathies, cardiomyopathies, etc.); electrolyte disorders (alterations in the concentration of blood electrolytes); toxic effects of certain drugs.

The stress electrocardiogram, on the other hand, is performed to assess the behaviour of blood pressure, cardiac rhythm and the possible appearance of signs or symptoms of cardiac distress during physical labour.

Who can perform the electrocardiogram?

There are no contraindications for performing the standard electrocardiogram.

The exercise ECG is, however, contraindicated for patients who cannot undergo physical exertion, who have ongoing ischaemia/arrhythmia and severe heart failure with symptoms at rest.

Is the ECG painful or dangerous?

The ECG lasts only a few minutes.

The test is safe and painless and there are no particular contraindications to the test.

How does the ECG work?

Ten electrodes are applied to the patient’s skin to record the heart’s electrical activity.

The electrodes are connected by electrical wires to a device called an electrocardiograph, which processes and prints the graphical trace (electrocardiogram) on paper.