The refilling of the ventricles and ventricular repolarization occur during which phase?

The refilling of the ventricles and ventricular repolarization occur during which phase?

• A. Diastole
• B. Systole
• C. Isovolumetric contraction
• D. Atrial systole

Answer: (A)

Ventricular filling and ventricular repolarization occur during diastole, the heart’s relaxation phase. When the ventricles relax, the atrioventricular valves open and blood flows from the atria into the ventricles, filling them. At the same time, the ventricles repolarize as they recover from contraction, which corresponds to the relaxation period on the ECG (the T wave). In contrast, systole is the contraction phase when the ventricles eject blood, so filling doesn’t happen then. The brief isovolumetric contraction phase also occurs during systole, with all valves closed and no volume change, so it isn’t filling. Atrial systole does contribute to final ventricular filling near the end of diastole, but the broad process of filling and ventricular repolarization aligns with diastole.

Ventricular filling and ventricular repolarization occur during diastole, the heart’s relaxation phase. When the ventricles relax, the atrioventricular valves open and blood flows from the atria into the ventricles, filling them. At the same time, the ventricles repolarize as they recover from contraction, which corresponds to the relaxation period on the ECG (the T wave). In contrast, systole is the contraction phase when the ventricles eject blood, so filling doesn’t happen then. The brief isovolumetric contraction phase also occurs during systole, with all valves closed and no volume change, so it isn’t filling. Atrial systole does contribute to final ventricular filling near the end of diastole, but the broad process of filling and ventricular repolarization aligns with diastole.