Electrophysiological Basis for Normal Automaticity (Impulse Formation) ... In a normal healthy heart, only cells in the regions of the SAN, AVN, and His-Purkinje conduction system have the property of automaticity, or the ability to spontaneously depolarize to threshold when left unstimulated.

What is automaticity of cardiac cells?

Automaticity is the property of cardiac cells to generate spontaneous action potentials. Spontaneous activity is the result of diastolic depolarization caused by a net inward current during phase 4 of the action potential, which progressively brings the membrane potential to threshold.

Does cardiac muscle have automaticity?

Contractility of Heart Muscle

Electrical conduction in the heart is unique and remarkable. Heart muscle possesses the following properties: Automaticity – pacemaker ability. Conductivity – each cell has ability to conduct impulses to the next cell.