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 141

ECG 141


Basic rhythm

Sinus rhythm at 50-63 bpm.

P waves

Significant negative portion in V1, prolonged duration at 110 ms.

PR interval

Prolonged at 440 ms.


Normal axis and morphology.

ST segment, T waves


QT interval



Left atrial hypertrophy.
Blocked P wave.
Prolonged PR interval.


Wenckebach type second degree A-V block, left atrial hypertrophy.


The PR interval longer than 300 ms and the narrow QRS complex morphology suggest an intranodal A-V block. On the left part of the trace, we notice a variation in the RR interval which is part of the prolongation of A-V conduction. In the precordial leads the first apparent P wave is conducted, the second is conducted with a very long PR interval and the third is blocked.


Conduction abnormalities


Reading level

2 / 3