The<unk>  is composed of four phases: phase 0 is depolarization, phase 1 is early repolarization, phase 2 is a plateau, phase 3 is rapid repolarization and phase 4 is the resting potential.  The different phases depend on the opening and/or closure of specific ion channels.
Ventricular action potential
Polarization density
QRS complex
RR interval
QT interval
Resting potential
PR interval
Membrane potential