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 012

ECG 012


Basic rhythm

Irregular narrow complex tachycardia ranging from 75 to 150 bpm.

P waves

Absent; regular and monotone oscillations of the baseline with a sawtooth or factory roof pattern (F waves) at a rate of 300/min.

PR interval

Not definable.


Normal axis and morphology.

ST segment


T waves

Appear normal (sometimes concealed by the F waves).

QT interval



F waves with "sawtooth" aspect typical for atrial flutter.
2:1 conduction and 4:1 conduction.


Typical atrial flutter with 2:1 or 4:1 variable A-V conduction.


The regular atrial activity at 300/min is characteristic of typical flutter, which is a reentry circuit in the right atrium with an anti-clockwise rotation. The A-V node cannot transmit impulses of such a high rate. It acts as a filter that protects the ventricles by avoiding too fast a rhythm. A-V conduction is usually 2:1. This can also be 3:1 or even 4:1, as with this trace, where the RR interval is sometimes doubled.


Narrow QRS complex tachycardia


Reading level

1 / 3