What is the term used to describe the relaxation phase of the heart?

The term for the relaxation phase of the heart is diastole. During diastole, the heart muscle relaxes, allowing the chambers of the heart to fill with blood from the body and the lungs. This phase is crucial because it ensures that the heart is adequately filled with blood before it contracts again in the subsequent phase known as systole, where the heart pumps blood out to the rest of the body.

Understanding this distinction between diastole and systole is fundamental in cardiovascular physiology, as it helps clarify how the heart manages blood circulation. The cardiac cycle refers to the complete sequence of events that occur in the heart during a heartbeat, which includes both systole and diastole but does not specifically refer to the relaxation phase alone. Arrhythmia refers to an irregular heartbeat, which, while significant, does not pertain to the relaxation phase of the heart.