Which statement accurately describes the relative refractory period?

The relative refractory period is a crucial phase in cardiac physiology that follows the absolute refractory period. During this time, the myocardial cells have begun to recover from the depolarization that occurred during an action potential, but they are not fully back to their resting state. The key aspect of the relative refractory period is that although the cells are still in a state of partial recovery, they can be stimulated to depolarize again, but only if the incoming stimulus is stronger than normal. This is why identifying this phase as the time when cells can be stimulated if the stimulus is strong enough is accurate.

In contrast, the other statements do not appropriately describe this physiological phase. The complete unresponsiveness to stimulation characterizes the absolute refractory period rather than the relative refractory period. The occurrence of the relative refractory period does not specifically align with the QRS complex on an electrocardiogram, which represents ventricular depolarization. Lastly, while it does relate to recovery, it does not solely refer to the recovery phase after depolarization; rather, it specifies a stage where stimulation is possible under certain conditions. Therefore, the correct understanding hinges on recognizing that a sufficiently strong stimulus can indeed elicit a response during this period.