At what point in the cardiac cycle is pressure highest?
The maximum ratio of pressure to volume (maximal active chamber stiffness or elastance) usually occurs at the end of ejection. Isovolumetric relaxation follows (phase IV), and when left ventricular pressure falls below left atrial pressure, ventricular filling begins.
What is cardiac diastole?
diastole, in the cardiac cycle, period of relaxation of the heart muscle, accompanied by the filling of the chambers with blood. Diastole is followed in the cardiac cycle by a period of contraction, or systole (q.v.), of the heart muscle.
What is the difference between the systolic and diastolic phases of the cardiac cycle?
Diastole and systole are two phases of the cardiac cycle. They occur as the heart beats, pumping blood through a system of blood vessels that carry blood to every part of the body. Systole occurs when the heart contracts to pump blood out, and diastole occurs when the heart relaxes after contraction.
How do you calculate heart rate from a cardiac cycle graph?
When the cardiac rhythm is regular, the heart rate can be determined by the interval between two successive QRS complexes. On standard paper with the most common tracing settings, the heart rate is calculated by dividing the number of large boxes (5 mm or 0.2 seconds) between two successive QRS complexes into 300.
Why is the maximum pressure in the left atrium lower?
Blood flows from the left atria into the left ventricle, and pressure in the left ventricle actually decreases because the heart is continuing its relaxation and expanding slightly faster than it is filling.
What is the gap between systolic and diastolic?
The top number (systolic) minus the bottom number (diastolic) is the pulse pressure. For example, if the resting blood pressure is 120/80 millimeters of mercury (mm Hg), the pulse pressure is 40 — which is considered a healthy pulse pressure. Generally, a pulse pressure greater than 40 mm Hg is unhealthy.
Why is systolic pressure higher than diastolic?
Systolic pressure reflects the force produced by the heart when it pumps blood out to the body, while diastolic blood pressure (the bottom number) is the pressure in your blood vessels when the heart is at rest.