Quick refresherDepolarization - Electrical dischargeRepolarization - Electrical recharge
PR Interval - From the very beginning f the P wave to the first deflection of the QRS complex. The PR Interval should end on the isoelectric line. The normal PR interval last from 120 ms to 200 ms (0.12-0.20 sec).
Blood pours into the right atrium from the vena cava and the left atrium from the pulmonary vein.The SA node fires a signal representing a P wave on the ECG. A this point the atria contract, ejecting their blood into the ventricles.As the impulse travels to the AV node, the PR segment shows the pause in electrical activity. This pause allows the ventricles to fill to capacity.The interventricular septum then depolarizes, and then the rest of the ventricular myocardium. We see this as a QRS complex.The blood ejects out of the ventricles. The Ventricular myocardium then recharges which is displayed as a T wave.