Term
In phase 1, what heart sounds are heard?
What is seen on an EKG?
What happens in phase 1? |
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Definition
the S4 sound, heart when the atria contracts. The p wave is seen as the atria depolarize
Phase 1 - atrial contraction. Atria fill the ventricles, then contract to add 10%. |
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Term
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Definition
| Left Ventricular End Diastolic Volume, seen in phase 1/2. Normally ~120 ml, when the volume of the LV is at it's max. |
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Term
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Definition
| Usually ~10 mmHg. # is higher if ventricular walls are stiff |
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Term
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Definition
| The a wave is seen in atrial pressure when the atria contract. |
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Term
What sound is heard in phase 2?
What is seen on the EKG?
What pressure changes occur in phase 2? |
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Definition
The S1 sound is heard as the AV valves close.
The QRS complex is seen as the ventricles depolarize.
Isovolumetric contraction - pressure in the ventricles sharply rises while volume does not change. |
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Term
What occurs in Phase 3?
What pressure and volume changes occur? |
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Definition
The semilunar valves open to release blood into the pulmonary trunk and aorta.
LAP begins to rise, Aortic and ventricular pressure rise up to a maximum of 120 mmHg. LV volume rapidly depletes. |
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Term
What occurs in phase 4? What are the pressure and volume changes?
What shows on the EKG? |
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Definition
End of ventricular emptying, Ventricular and aortic pressure falls. Aortic pressure falls to a min. of 80. LAP continues to rise due to filling. LVESV reached.
T wave - repolarization of the ventricles. |
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Term
| What is the c wave in phase 2? |
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Definition
| The mitral valve pushes back into the atrial due to rising ventricular pressure. |
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Term
| What is LVESV? What happens if it increases above normal? |
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Definition
| Minimum volume seen at the end of systole, usually ~70 ml. If increased, contractility is decreased. |
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Term
What sound is heard in phase 5?
What pressure changes occur? |
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Definition
S2 occurs as the semilunar valves close. The beginning of diastole.
Isovolumetric relaxation - ventricular pressure decreases sharply. Atrium finishes filling.
v wave - dichrotic notch, made by closing of the aortic valve |
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Term
How do you calculate ejection fraction?
What is a normal ejection fraction? |
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Definition
EF = SV/EDV --> (EDV-ESV)/EDV
Normal is ~0.55 |
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Term
What sounds is heard in phase 6?
What pressure and volume changes occur? |
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Definition
The S3 sound is heard when blood rushes into the ventricles.
Rapid filling - when ventricular pressure drops below atrial pressure, the AV valves open. LV volume steadily rises. |
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Term
What is phase 7?
What pressure or volume changes occur? |
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Definition
| Reduced filling - ventricular filling slows as it reaches LVEDV. A very slight increase in LAP. |
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Term
| What is the difference between the cardiac cycle of the left side of the heart and the right side? |
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Definition
| The volumes are identical, the right side is under a reduced amount of pressure. |
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Term
| What is stroke-work output? |
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Definition
The amount of energy that the heart converts into work during each heartbeat. Major proportion is external work, which moves blood from low pressure to high pressure veins.
Represented by the area inside a Cardiac Volume-Pressure loop |
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Term
| What is phase 1 on the volume pressure loop? |
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Definition
| Period of filling, measured from when the mitral valve opens (LVESV) to when the mitral valve closes (LVEDV). |
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Term
| What is Phase 2 on the volume pressure loop? |
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Definition
| Isovolumetric contraction. Completely vertical, so all a measure of pressure. From when the mitral valve closes to when the Aortic valve opens. |
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Term
| What is Phase 3 on the volume pressure loop? |
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Definition
| Period of ejection - curve from C to D where the ventricle empties. From when the aortic valves to when it closes. |
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Term
| What is phase 4 on the volume pressure loop? |
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Definition
| Isovolumetric relaxation, all valves closed. Pressure dropping in ventricle, atria continues to fill. |
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Term
| What happens if you increase volume past the normal volume of a V-P curve? |
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Definition
Frank Starling's law - increase in LVEDV will result in an increase in force of contraction
After 150 mL, pericardium restricts stretch, seeing a decrease in force of contraction. |
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