Which phase of the cardiac cycle is associated with repolarization?

Repolarization in the cardiac cycle primarily occurs during the third phase. This phase is characterized by the electrical activity that allows the heart muscle cells to recover after the contraction has taken place.

During this phase, the potassium channels open, allowing potassium ions to flow out of the cells, while calcium channels close. This change in ion concentration helps the cardiac muscle cells return to their resting state after depolarization, which is when the muscle cells contract. It is crucial for the timing of the heart's electrical activity, as proper repolarization ensures that the heart has adequate time to fill with blood before the next contraction.

Understanding this phase is essential for recognizing how the heart maintains a regular rhythm and functions efficiently. Any dysfunction in this repolarization process can lead to arrhythmias and other cardiac complications.