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 129

ECG 129


The trace was obtained using a Holter monitor with 2 leads. Basic rhythm

Sinus rhythm at 75 bpm. The 6th P wave is followed by a prolonged PR interval with the start of narrow QRS complex tachycardia. A small R wave is present at the end of the QRS complex in tachycardia.

PR interval

Normal duration.


Normal duration.

QT interval



Narrow QRS complex tachycardia.
Prolonged PR interval.
r' wave at the end of the QRS complex.


Start of nodal tachycardia.


The prolonged PR interval at the start of the tachycardia corresponds to the fact that the impulse crosses the A-V node using the slow pathway, before returning through the fast pathway, causing typical nodal tachycardia. During the tachycardia, the retrograde P wave is visible in the form of a small R wave at the end of the QRS complex.


Narrow QRS complex tachycardia


Reading level

3 / 3