Pressures
At this moment in the cardiac cycle, ventricular pressure is falling rapidly, semilunar valves have just closed, atrial pressure is still higher than ventricular pressure, and no blood is moving between chambers.
What is isovolumic relaxation?
This phase begins immediately after atrial contraction, when both atrioventricular and semilunar valves are closed and ventricular pressure is rising without a change in volume.
What is isovolumic contraction?
At this moment, ventricular volume is maximal, ventricular walls are thinnest, atrial volume is minimal, and the atrioventricular valves have just closed.
What is end-diastole?
This mechanical event occurs when ventricular pressure exceeds atrial pressure, causing closure of the atrioventricular valves and marking the onset of systole.
What is the S1 heart sound? (AV Valve closure)
This physiologic variable increases when ventricular filling rises, stretches myocardial fibers, and proportionally increases both contraction force and ejection.
What is preload?