A normal ECG has the readings as ;
1.Depolarization, 2. Q, 3. R, 4.Depolarization, 5. Repolarization
In a normal ECG. The tiny wave at the beginning is called the P wave. This wave represents atrial depolarization. The graph remains straight for a fraction of a second, representing conduction of the impulse through the AV node to the ventricles. It begins with a slight downward deflection called the Q wave, after which ventricular contraction begins. Next we see a large peak called the R wave, which subsequently plummets down giving rise to the S wave. When the impulse reaches the ventricles, we see this QRS wave complex. This whole complex represents ventricular depolarization. After the ventricles have finished contracting they must undergo repolarization. This is seen as the upward deflection after the QRS complex called the T wave. This represents ventricular relaxation.