How long is the effective refractory period of ventricular muscle

The reason for the long effective refractory period of ventricular muscle is that the depolarization speed and amplitude of phase 0 of the action potential are slow, and the duration of phases 1 and 2 of repolarization is short, resulting in a long action potential duration and a long effective refractory period.

Answer to the question:

The reason for the long effective refractory period of ventricular muscle is that the depolarization speed and amplitude of phase 0 of cardiac muscle action potential are slow, and the duration of phase 1 and phase 2 of repolarization is short. Therefore, the whole action potential duration is longer, and the effective refractory period is relatively longer

. Cardiac myocytes produce action potential when stimulated, which includes three stages: depolarization, repolarization and hyperpolarization.

2. Effective refractory period: Effective refractory period refers to the period of time from depolarization of phase 0 of action potential to recovery of membrane potential to-60mV in phase 3 of repolarization after one excitation. The significance of effective refractory period of ventricular muscle lies in ensuring that cardiomyocytes will not receive stimulation again before contraction, thus ensuring normal systolic and diastolic functions of the heart

.

The long effective refractory period of ventricular myocytes is due to the slow depolarization speed and small amplitude of phase 0 of cardiac myocytes action potential, and the short duration of repolarization phase 1 and phase 2, resulting in the long duration of the whole action potential. The effective refractory period of ventricular myocytes is affected by many factors, including intracellular calcium concentration, sodium channel function, potassium channel function, adrenergic receptor activity, etc.