GROSS ANATOMY

Detailed explanation-1: -The QRS complex is a record of the movement of electrical impulses through the lower heart chambers (ventricles). The ST segment shows when the ventricle is contracting but no electricity is flowing through it. The ST segment usually appears as a straight, level line between the QRS complex and the T wave.

Detailed explanation-2: -The QRS complex represents the electrical impulse as it spreads through the ventricles and indicates ventricular depolarization. As with the P wave, the QRS complex starts just before ventricular contraction.

Detailed explanation-3: -The QRS denotes depolarization of ventricular muscle and it appears 0.16 seconds after the P wave, during this event, due to ventricle contraction, the ventricular pressure rises rapidly. The T wave reflects depolarization of both ventricles and they begin to relax [3, 4], see Fig. 4.4.

Detailed explanation-4: -The QRS wave of the electrocardiogram represents ventricular depolarization, which is followed by contraction and an increase in pressure in the ventricles (ventricular systole). The T wave of the ECG represents ventricular repolarization and relaxation of the ventricular muscles (ventricular diastole).