<prompt> Depolarisation of atria on ECG is seen asP-waveQRS complexT-waveST segment  <response>: P wave shows atrial depolarizationQRS complex shows ventricular depolarization T wave shows ventricular repolarizationST segment represents the duration from the end of ventricular depolarization to the beginning of ventricular repolarizationRef: Textbook of medical physiology by N Geetha,2nd edition, page no. 136 