Cardiac Simulation Flashcards
What occurs when the pressure in the left ventricle exceeds that of the aorta?
Aortic valve opens
What happens when the pressure in the left ventricle exceeds the pressure in the left atria?
Mitral valve closes
What occurs when the pressure in the aorta exceeds that of the left ventricle?
Aortic valve closes
What happens when the pressure in the left atria exceeds that of the left ventricle?
Mitral valve opens
Describe the Atrial Systole of the Cardiac Cycle.
Filling of the ventricles until the atrioventricular valves close as the pressure in the ventricles exceeds that in the atria.
Describe the Isovolumic Contraction of the Cardiac Cycle.
Left ventricular pressure increases until the aortic valve opens.
Describe the Ejection of the Cardiac Cycle.
Ventricular muscles shorten and contract, ejecting blood from the heart in two phases: rapid and reduced.
Describe the Isovolumic Relaxation of the Cardiac Cycle.
The left ventricular pressure decreases below the the aortic pressure and so the aortic valve closes.
Describe the Ventricular Filling of the Cardiac Cycle.
The left ventricle falls below atrial pressure and so the mitral valve opens and the atria can begin to fill the ventricles in two stages: rapid and reduced.
Why is there Reduced Ejection?
Reduced ejection occurs because of:
1) Increased after load as it has increased due to the ventricles pumping blood out of the aorta
2) Cardiac muscle has already shortened a lot and so it has already shortened sarcomeres.
Why is there Reduced Filling?
The tension increases as the ventricles are filled and so when they are close to being full they resist filling more and so it fills slower.
What is the normal pressure of the right atria?
2 mmHg
What is the normal pressure of the left atria?
6 mmHg
What is the normal pressure of the right ventricle?
2 mmHg
What is the normal pressure of the left ventricle?
6 mmHg
What is the diastolic pressure of the left ventricle?
6 mmHg
What is the systolic pressure of the left ventricle?
120 mmHg
What is the normal aortic pressure?
80 mmHg
What is the diastolic pressure of the right ventricle?
2 mmHg
What is the systolic pressure of the right ventricle?
25 mmHg
What is the a-wave in the venous pulse caused by?
Atrial contraction
What is the c-wave in the venous pulse caused by?
Ventricular contraction
What is the v-wave in the venous pulse caused by?
Filling and emptying of the atria
What is the cause of the 1st heart sound (S1)?
Closure of the mitral and tricuspid valves
What is the cause of the 2nd heart sound (S2)?
Closure of the aortic and pulmonary valves
What is the cause of the 3rd heart sound (S3)?
Occurs at the start of diastole and is caused by mitral regurgitation
What is the cause of the 4th heart sound (S4)?
Occurs right before systole and right after atrial contraction and is caused by a forceful contraction to overcome a hypertrophic ventricle
What is pulmonary wedge pressure?
It is the pressure measured by using a pulmonary catheter with a balloon wedged into a small pulmonary arterial branch.
It measures the pressure in the left atria and increases in pressure may be due to mitral stenosis.
What are the causes of systolic murmurs?
1) Stenosis of the aortic or pulmonary valves
2) Incompetence of the mitral and tricuspid valves
What are the causes of diastolic murmurs?
1) Stenosis of the mitral and tricuspid valves
2) Incompetence of the aortic and pulmonary vales
Describe physiological splitting.
Caused during inspiration which creates a larger preload and the left ventricle empties before the right so that the pulmonary valve closes after the aortic valve.
Describe persistent splitting.
Caused by right bundle branch block as RV systole is delayed by the blocked conduction and it appears throughout respiration (hence persistent).
Describe paradoxical splitting.
Caused by left bundle branch block as LV systole is delayed and the aortic valve closes after and this appears with expiration.
How does inspiration influence splitting of the 2nd heart sound?
Inspiration increases the preload of the RV and therefore increases its fulling which delays the closure of the pulmonary valve.
How does inspiration affect physiological splitting?
It exaggerates it
How does inspiration affect paradoxical splitting?
It attenuates it as it delays the RV conduction as well and so the difference of it and the LV conduction is lessened.
