Our ECG Interpretation Training and Reference Guides provide basic lessons for ECG analysis as well as a quick reference guide for over 40 types of ECG tracings. The arrhythmia drills and quizzes allow you to practice ECG interpretation.

An electrocardiogram or ECG, records electrical activity in the heart. An ECG machine records these electrical signals across multiple heart beats and produces an ECG strip that is interpreted by a healthcare professional.

How Electrocardiograms Work - ECG Strips

To briefly summarize the components of a normal ECG tracings, it consist of waveform components which indicate electrical events during one heart beat. These waveforms are labeled P, Q, R, S, T and U.



P wave is the first short upward movement of the ECG tracing. It indicates that the atria are contracting, pumping blood into the ventricles.



The QRS complex, normally beginning with a downward deflection, Q; a larger upwards deflection, a peak (R); and then a downwards S wave. The QRS complex represents ventricular depolarization and contraction.



The PR interval indicates the transit time for the electrical signal to travel from the sinus node to the ventricles.



T wave is normally a modest upwards waveform representing ventricular repolarization.











