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 133

ECG 133


Basic rhythm

Regular at 100 bpm.

P waves

Preceded by a spike. Delay between the spike and the QRS complex of 260 ms.


Prolonged. Axis -50°. Non-progression of the R wave in the precordial leads. Micropotentiels in the precordial leads.

QT interval



Left axis deviation.
Atrial spike with first degree AV block.


Pacemaker working normally in AAI mode. First degree A-V block. Left anterior hemiblock. Micropotentiels.


The P waves are preceded by a spike, because the atria are paced. The PR interval (in this case the interval between the spike and the R wave) is prolonged, a sign of a first degree A-V block (this is linked to the DDD mode of the pacemaker). The QRS complexes are wide with left axis deviation due of a left anterior hemiblock. On this ECG trace the pacemaker is working in AAI mode. It only paces the ventricles if the A-V delay exceeds a predetermined value, which is usually programmed to be around 300 ms in order to allow normal ventricular depolarisation to occur as much as possible.




Reading level

2 / 3