QRS complex is due to
P wave is primarily produced by atrial depolarization, the QRS complex is dominated by ventricular depolarization, and the T wave by ventricular repolarization. The U wave is an inconstant finding that may be due to ventricular myocytes with long action potentials. Ref: Ganong&;s Review of medical physiology 25th edition. Page: 522
Ventricular repolarization
Atrial depolarization
Conduction through AV node
Ventricular depolarization
Cardiovascular system