I-ECG ibonisa i-atrial systole. oku ke kubizwa ngokuba yi-P-wave. Emva koko kwenzeka i-nentricular systole. Oku ke kubizwa ngokuba kuyi-QRS okanye i-QRS-complex. Ikuthiwa yi-complex kuba kukho amaza aziintlobo ezintathu ngokwahlukana kwazo. Iliza eliyi- Q-wave, i-R-wave, kunye ne-S-wave. emva koko i-ECG ibonisa i-ventricular diastole. Le ke ibizwa ngokuba yi-T-wave. I-Atrial diastole yenzeka ngoko nayo. kodwa ayibonakali yahlukene kwi-ventricular diastole.