During what phase of the cardiac cycle does the atrial pressure exceed ventricular pressure, allowing blood to flow from the atria to the ventricles?

The phase of the cardiac cycle when atrial pressure exceeds ventricular pressure, facilitating the flow of blood from the atria to the ventricles, occurs during ventricular diastole. During this phase, the heart muscles relax, and as the ventricles fill with blood, the pressure within them decreases. Concurrently, the pressure in the atria increases as they receive blood from the systemic and pulmonary circulation. When the atrial pressure surpasses that of the ventricles, the atrioventricular (AV) valves open, allowing blood to flow into the ventricles.

This essential process ensures that the ventricles are adequately filled with blood prior to the next contraction. It is crucial for normal heart function, as proper filling of the ventricles is necessary for efficient pumping and maintaining adequate circulation throughout the body. This phase is characterized by passive filling of the ventricles, with the valves being opened due to the pressure gradient created by the relationship between atrial and ventricular pressures.