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 139

ECG 139


Basic rhythm

Sinus rhythm at 60 bpm.

P waves

Negative in I and aVL.

PR interval



Right axis deviation with QRS axis +120 degrees. Constant reduction in V1 to V6 potential.

QT interval



Negatives P waves and QRS complexes.
Decreased amplitude of the QRS complexes.




The negative P waves in leads I and aVL make us suspect that the electrodes have been wrongly positioned or that there is a left atrial rhythm. These abnormalities, as well as the right axis deviation and decreasing amplitude of the QRS complexes in the precordial leads (which would not be the case if the electrodes had been inverted) allow us to give the diagnosis of dextrocardia. The next ECG (no. 140) shows an ECG recording of the same patient, carried out using precordial electrodes on the right precordium.


Various cardiopathy


Reading level

3 / 3