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 002

ECG 002


Basic rhythm

Narrow complex tachycardia at 107 bpm.

P waves

Negative in inferior leads, positioned exactly in the middle of the RR interval.

PR interval

Prolonged at 280 ms. RP'/P'R ratio =1.


Normal axis and morphology.

ST segment

Depression from V2 to V5 and in II and aVF.

T waves

Normal, QT interval: normal.


Negative P' wave in II,III and aVF located exactly in the middle of the RR interval.
Small negative r' wave at the end of the QRS complex corresponding to a negative retrograde P' wave.


Typical atrioventricular nodal reentrant tachycardia with 2:1 A-V block.


When the A-V conduction is 1:1 the P wave is usually concealed in the QRS complex and is therefore invisible. When the A-V conduction is blocked, in 80% of the cases it is blocked in the infra-nodal conduction pathways. In this case the P' wave is blocked every 2 beats and is not followed by a QRS complex. This P wave becomes clearly visible with the particular characteristic of being exactly in the middle of the RR interval, which is not seen in other tachycardias. At the end of the QRS complex, a small P' wave can also be seen. The ST segment depression is non-specific and is secondary to the tachycardia. If the A-V block disappears, the heart rate doubles. This often causes a transitory conduction disturbance, which transforms narrow complex tachycardia into broad complex tachycardia.


Narrow QRS complex tachycardia


Reading level

2 / 3