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 021

ECG 021


Basic rhythm

Sinus rhythm, regular at 70 bpm.

P waves


PR interval

Elongated (260 ms), second P wave blocked in the peripheral leads.


Enlarged (130 ms), right axis deviation, rSR' in V1.

ST segment


T waves

Negative in II, III, aVF and in V2 and V3.

QT interval



First degree AV block.
Blocked P wave.
Rigth Bundle Branch Block (RBBB).
Rigth axis deviation.


First degree A-V block (prolonged PR interval) with second degree A-V block, Mobitz type II. Complete right bundle branch block. Left posterior hemiblock.


This trace shows a fragile A-V conduction and a bifascicular block (complete right bundle branch block + posterior hemiblock). Of the various branches of the bundle of His, only the left anterior hemibranch is still functional. All these conduction disturbances anticipate the occurrence of a complete A-V block and indicate the implantation of a permanent pacemaker.


Conduction abnormalities


Reading level

2 / 3