What does systole refer to in relation to the heartbeat?

Systole specifically refers to the phase of the heartbeat during which the heart muscles contract. This contraction is essential as it pumps blood out of the heart and into the arteries, delivering oxygen and nutrients to the body. Systole occurs after diastole, which is the relaxation phase when the chambers of the heart fill with blood. Understanding this phase is critical in assessing cardiac function, as a failure to properly contract can lead to inadequate blood circulation and various cardiovascular issues. The contraction during systole is initiated by electrical impulses from the heart's conduction system, highlighting its importance in coordinating efficient heart function.