During which phase does rapid ventricular filling occur due to AV valve opening?

During which phase does rapid ventricular filling occur due to AV valve opening?

• A. Late systole
• B. During atrial contraction
• C. During isovolumetric contraction
• D. Early diastole

Answer: (D)

When the AV valves open at the start of diastole, the ventricle suddenly experiences the higher atrial pressure pushing blood in, causing rapid passive filling. This happens in early diastole after the period of isovolumetric relaxation, as ventricular pressure drops below atrial pressure and a large pressure gradient drives a quick inflow of blood until ventricular pressure rises again. After this rapid burst, filling slows (diastasis) and later, toward the end of diastole, atrial contraction contributes additional filling. So the rapid ventricular filling due to AV valve opening occurs in early diastole.

When the AV valves open at the start of diastole, the ventricle suddenly experiences the higher atrial pressure pushing blood in, causing rapid passive filling. This happens in early diastole after the period of isovolumetric relaxation, as ventricular pressure drops below atrial pressure and a large pressure gradient drives a quick inflow of blood until ventricular pressure rises again. After this rapid burst, filling slows (diastasis) and later, toward the end of diastole, atrial contraction contributes additional filling. So the rapid ventricular filling due to AV valve opening occurs in early diastole.