HRR: Cardiodynamics II Flashcards
What causes the aortic valve to open?
The pressure in the ventricle exceeds that of the aorta.
The valve will close again once the ventricular pressure falls below the aortic pressure.
At what point do we hear S1?
End diastolic.
S1 is associated with the closure of the mitral and tricuspid valves.
At what point do we hear S2?
End systolic.
S2 is associated with the closure of the aortic and pulmonary valves.
What creates an S3 sound?
Abnormal turbulence heard during ventricular filling.
S3 is often associated with heart failure or volume overload.
Describe S4.
The atrium is trying to push blood into a stiff ventricle, creating audible turbulence; this can be heard right before end diastole.
S4 is often associated with decreased ventricular compliance.
What does the ESPVR slope measure?
The maximal pressure developed by the left ventricle at any given volume; it is a measure of contractility.
An increased slope indicates more contractility, while a decreased slope indicates less contractility.
What is the significance of the pressure-volume loop in the cardiac cycle?
It illustrates the relationship between pressure and volume changes during the cardiac cycle phases.
The loop includes phases like isovolumic contraction, ejection, and filling.
Fill in the blank: The pressure in the ventricle must exceed that of the _______ for the aortic valve to open.
aorta
True or False: S3 is a normal heart sound in elderly patients.
True.
In some elderly patients, S3 can be a normal finding, while in others, it may indicate heart failure.
What does a decreased slope in the ESPVR indicate?
Less contractility.
This can suggest poor cardiac function or heart disease.
What does the slope of the EVPR measure?
It measures the compliance of the heart
An upward shift indicates decreased compliance, while a downward shift indicates increased compliance.
What regulates stroke volume?
Preload, after-load, and contractile state
These factors influence the volume of blood ejected by the heart.
Preload is a _______ regulator of stroke volume.
Positive
After-load is a _______ regulator of stroke volume.
Negative
What is after-load?
The pressure the heart needs to overcome to pump blood out of the ventricle during contraction
What is preload?
The volume of blood in the ventricles at the end of diastole
How do we measure preload?
EDV
How can sympathetic stimulation increase afterload?
By increasing vasoconstriction
How does a change in preload impact stroke volume?
Decreased preload will decrease stroke volume, and increased preload will increase stroke volume
How does increased preload impact a PV loop?
SV increases, EDVPR does not change
How does increased afterload impact stroke volume?
It will decrease it
What happens to preload after a sudden increase in afterload?
It will decrease stroke volume which will increase preload in the following cycle
This occurs because the sudden increase in afterload prevents the normal amount of blood from being ejected, adding more blood to what will be brought in during diastole.
What is inotropy?
Being able to increase the force of contraction
How does inotropy impact stroke volume?
Increases it
Inotropy is associated with making more _______ available to myofilaments.
Calcium
What is the impact of inotropy on preload?
Inotropy lowers preload
Inotropy refers to the force of heart muscle contraction, and a positive inotropic effect can lead to lower preload.
What can cause a larger peak systolic pressure?
Positive Inotropy
Positive inotropic agents increase the strength of heart contractions, which can result in higher peak systolic pressure.
