Simultaneous contraction of the atria followed by simultaneous contraction of the ventricles. The sequence of events in one heartbeat.
One complete sequence of contraction and relaxation of the heart.
The repeated beating of the heart, formed of the diastole and systole.
Cycle of events during which an electrical impulse is conducted through special fibers in the heart muscle, causing contraction of the atria followed by contraction of ventricles, which action pumps blood through the body. The cycle can be shown on an electrocardiogram as a series of waves, termed P, Q, R, S, and T waves; changes in wave patterns indicate abnormalities in the cardiac cycle.
The various sequential movements of the heart that comprise the rhythmic relaxation and expansion of the heart muscles as first the atria contract and force the blood into the ventricles (diastole), which then contract (systole) to pump the blood round the body.
The period from the beginning of one heartbeat to the beginning of the succeeding beat, including systole and diastole. Normally, the atria contract immediately before the ventricles. The ordinary cycle lasts 0.8 sec with the heart beating approx. 60 to 85 times a minute in the adult at rest. Atrial systole lasts 0.1 sec, ventricular systole 0.3 sec, and diastole 0.4 sec. Although the heart seems to be working continuously, it actually rests for a good portion of each cardiac cycle.
The heartbeat is a rapid sequence of events that occurs within a fraction of a second. It consists of three distinct phases: diastole, atrial systole, and ventricular systole. During diastole, the heart undergoes relaxation. Subsequently, in atrial systole, the upper chambers of the heart, known as the atria, contract. Finally, in ventricular systole, the lower chambers of the heart, known as the ventricles, contract. The sinoatrial node, which serves as the natural pacemaker of the heart, plays a vital role in coordinating the timing of these phases by transmitting electrical impulses to both the atria and the ventricles.
The sequence of contractions of the heart’s chambers.