• Normal ECG consists of P wave, QRS complex, and T wave
– P wave is first positive deflection on ECG and represents atrial depolarization
– P‐R interval is time it takes for electrical impulse to be conducted through atria and AV node up to instant of ventricular depolarization
– QRS complex represents ventricular depolarization
– ST segment represents early part of repolarization of right and left ventricles