ECG Directory

Welcome to this interactive ECG course.

Although it is one of the oldest paraclinic exams, dating back to the late 19th century, the ECG is still of crucial clinical use. This examination often still poses problems of interpretation to the medical practitioner.

This course aims to help the student, the practicing physician and even the trained cardiologist to improve his knowledge in electrocardiography. It consists of 250 traces of varying complexity with a description of each one by experts. This allows the reader to compare his analysis with that of the experts. In addition, the areas of interest of the ECG can be activated to be clearly highlighted.

We hope that these plots will be useful to readers and will improve their knowledge.

The ECGs are available sorted by keywords and categories.

ECG 043

ECG 043


Basic rhythm

Sinus rhythm at 75 bpm.

P waves


PR interval



Normal axis and morphology; one enlarged QRS complex in the precordial leads at the end of the preceding T wave.

ST segment


T waves

Negative in all leads, except in aVR. Alternation of waves with very large and very small amplitude; U wave visible in the precordial leads.

QT interval

Prolonged (at around 560 ms). An artefact is to be noted in V6 after the fifth QRS complex.


QT interval alternance.
Prolonged QT interval.


Acquired long QT syndrome with alternation of the repolarisation phase.


The alternation of the QT interval signals the occurrence of torsades de pointes. The ventricular extrasystole that occurs at the end of the T wave is due to early post-depolarisation, which can initiate a torsade de pointe. The cause of the QT interval prolongation must be investigated. Most often, it is a side effect of antiarrhythmic treatment.


Prolongation of the QT interval


Reading level

2 / 3