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 168

ECG 168


Baseline rhythm

Regular at 70 bpm.P-waves: visible after the QRS complex on the tracing on the left and negative in II, III and aVF. Normal P-waves on the right.PR interval: normal on the right.QRS: broadened when it is preceded by a spike (180 ms); normal axis, duration when it is preceded by a P-wave. Micropotentials in the peripheral leads.ST segment: isoelectric.T-waves: negative in the precordial leads.QT interval: normal.


Normal function of VVI pacemaker.
Negatives T waves.


Chatterjee phenomenon with intermittent pacing.


During the time that the ventricular pacing is interrupted, we can see negative T-waves for a duration of time proportional to the pacing time. This is due to a ‘memory’ effect of the ventricle which is termed Chatterjee phenomenon. It is a common observation of no significant clinical sequelae, but which must not be interpreted wrongly as ischemia or other cardiac pathology. This phenomenon can also be encountered with intermittent bundle branch block.




Reading level

1 / 3