<prompt> QRS complex is due toVentricular repolarizationAtrial depolarizationConduction through AV nodeVentricular depolarization  <response>: 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 