Answer:
QRS complex
Explanation:
The electrocardiogram represents the event of one heartbeat in the form of three distinct waves. The QRS complex is the second wave of ECG that starts as a downward deflection. It continues as an upright and triangular wave. It represents rapid ventricular depolarization. During the QRS complex, the action potential spreads through contractile fibers of ventricles. The QRS complex is followed by the T wave that represents the ventricular repolarization. QRS complex of ECG is preceded by the P wave that represents atrial depolarization.
