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 004

ECG 004


Basic rhythm

Narrow complex tachycardia, regular at 170 bpm.

P waves

Negative in I, II, III and aVF (where they are superimposed on the T wave, of which they increase the negativity); positive although poorly visible in V1 and V2.

PR interval

RP'< P'R.


Normal axis and morphology.

ST segment


T wave

Negative in the inferior leads, V5 and V6.

QT interval



Negative P' waves in II,III and aVF and positives in V1 and V2.
Narrow QRS complexes tachycardia.
Interval RP' < P'R.


Orthodromic atrioventricular tachycardia with left infero (postero)-septal accessory pathway.


The chronological relationship between the QRS complex and the P' wave (here RP'< P'R) is crucial in the differential diagnosis of narrow complex tachycardias. The negative P' wave in the inferior leads reflects the retrograde activation of the atria. The positive P' wave in V1 locates the left-sided accessory pathway. In sinus rhythm, to identify Wolff-Parkinson-White syndrome, the QRS complex must be deformed by a delta wave. If the delta wave is absent, the accessory pathway conducts only in the retrograde direction ("concealed" accessory pathway).


Narrow QRS complex tachycardia


Reading level

2 / 3