The phase II plateau phase is the second phase of the repolarization process in ventricular myocytes, or slow repolarization, where the repolarization process is slow and unique to cardiac myocytes. The process of ventricular repolarization is relatively slow and is divided into four phases, including the first phase of rapid repolarization, the second phase of the plateau phase or slow repolarization, the end of the third phase of rapid repolarization, and the fourth phase of the resting phase. After the membrane potential of about 0mV in the phase II plateau phase or slow repolarization phase, the repolarization process is quite slow, the inward current (inward flow of calcium ions) is in equilibrium with the outward current (outward flow of potassium ions), and the action potential map is relatively flat, and this phase is equivalent to the S-T segment of the electrocardiogram, which is referred to as the plateau phase because of the long duration of this process.