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30 Cards in this Set

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Blood flow through heart beginning with VC.

Compare pressures on each side of heart.
VC==>RA-->RV-->PA-->PV-->LA--LV

P in R side of heart is low (2 mmHg)
P in L side of heart is highest in LV (LA is pretty low)

LV: 120/5
Ao: 120/80
What is the primary pumping chamber of the heart?
LV
Cardiac Output = ?
Cardiac Output = Stroke Volume (cc's per beat out of ventricle) x Heart Rate
Blood Pressure = ?
Cardiac Output x Systemic Vascular Resistance (presented by aa of body)
If runner has increased blood flow during exercise, what is the effect on blood pressure?
Although BP = Q x systemic vasc resist, BP stays the same, but systemic vascular resistance decreases--runners need to cool down so BP doesn't drop?
What are the components of diastole?
Isovolumic relaxation
Rapid Ventricular Filling (increase in volume)
Atrial Contraction (kick)
Describe volumic changes during LV filling during the cardiac cycle.
Systole: volume drops and stops

Diastole: rapid filling, nothing happens, and then more filling (atrial kick)
Systole begins with closure of the ___________
mitral valve
Diastole begins with closure of the ____________
aortic valve
What are the stages of systole?
Isovolumic contraction (mitral and aortic valves closed), when LV Pressure exceeds aortic Pressure, aortic valve opens

[S1: closure of mitral and aortic valves]
S1 vs S2 events
S1: mitral and tricupsid closure
S2: aortic and pulmonic closure
How does splitting of the second heart sound occur?
Aortic valve closes before pulmonic closure and these events differ even more in time upon inhalation
Events of systole vs events of diastole
Systole:
Systole begins when mitral valve closes (triscupid valve closes too)
Pressure builds with ISOVOLUMIC CONTRACTION
Pressure opens pulmonic and aortic valves
Ejection

Diastole:
Begins when aortic and pulmonic valves close
As ventricles relax, pressure falls via ISOVOLUMIC RELAXATION
When pressure low enough, mitral and tricuspid valves open
Results in PASSIVE VENTRICULAR FILLING
Followed by ATRIAL KICK
Compliance vs Stiffness
Compliance: proportional to deltaV/deltaP (more compliant less of a change in P with a change in V; a good thing)

Stiffness: deltaP/deltaV
In a filling curve (P vs V), how would you identify a non-compliant LV?
Higher change in Pressure for any given Volume (up and to the left)
What are causes of diastolic dysfunction (stiffness)?
LV Hypertrophy (chronic HTN, valvular heart dz, cardiomyopathy)

(anything causing LV to stretch or thicken)

Myocardial ischemia or infarction
Preload vs Afterload
Preload = Wall tension during diastole (ventricular filling)

Afterload = Wall tension during systole (ventricular ejection; EMPTYING)

Where wall tension = P x radius (of sphere)/2h

h=wall thickness
What is the most important determining factor of preload? Why?
Pressure change during diastole is low, but volume change is huge so radius increases!

Wall tension = P x r/2h
What is the most important determining factor of afterload? Why?
Systolic Pressure (BP)

As soon as mitral valve closes, pressure increases a lot
How can you increase preload? Decrease?
Inc: Give fluid

Dec: Diuretic
How is afterload increased?
Decreased
Any drug that increases, lowers BP
Frank-Starling curves demonstrate what relationship?
Preload on x-axis (LV End-Diastolic Pressure)
Cardiac output on y-axis

As increase preload, cardiac output increases, but eventually levels off
As you increase LVDP, you increase ________.
Stroke volume (cardiac output)
How would a heart failure Frank-Starling curve appear?
Would have decreased stroke volume (cardiac output) for a given LV EDP, so upon administration of fluid (to inc volume and then radius) wouldn't get as much of an inc'd output
How is LA pressure measured?
Catheterize pulmonary arteriole (Right side of heart) bc will measure Pressure of Pulmonary Vein which = LA pressure
What does the Fick Method measure?
Measures cardiac output

Done with Waters Hood
What is the Fick Principle?
Higher cardiac output will result in higher venous oxygen saturation (less deoxygenated blood on return of RBCs to lungs)
How is oxygen saturation of the pulmonary vein measured?
Measure from any artery (only difference is oxygen taken by heart which is minimal)
If the cardiac output is low, the mixed venous O2 content is __________ than normal.
Lower than normal
What happens to the Frank-Starling curve with a surge of epinephrine?
Higher cardiac output, shift curve up and to left