Absolute refractory period of hea is the gap of time in which

Absolute: Is the period of time during which a second action potential ABSOLUTELY cannot be initiated, no matter how large the applied stimulus is. Relative: Is the interval immediately following the Absolute Refractory Period during which initiation of a second action potential is INHIBITED, but not impossible. Ref: guyton and hall textbook of medical physiology 12 edition page number:174,175,176