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What percentage of cardiac output does the atrium contribute?
20-25%
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Closure of Atrioventricular (AV) what heart sound?
S1 "Lub"
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Closure of Semilunar valve What sound?
S2 "Dub"
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When are the coronary parties perfused?
During diastole or ventricular relaxion
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What is cardiac output?
Stroke volume X heart rate
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What is stroke volume?
The amount of blood ejected from the heart with each contraction. Or end diastolic volume-End systolic volume
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What is the average amount of stroke volume in an adult?
70 ml
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What is average adult cardiac output?
- 4-8 liters per minute
- ex. pulse 60
- Stroke vlo.70
- 70 ml X 60 bpm = 4200 ml/min or 4.2 L/min
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Does bradycardia cause low or high cardiac output?
- low
- ex. sv=70 bpm=40 70X40= 2800ml/minor 2.8 lit/min
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What can too much beta blocker cause?
Too slow of heart rate. Decreased cardiac output.
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What is ejection fraction (EF)?
Stroke volume/(Divided by)End diastolic volume, it = the % if total blood ejected from the heart with each beat.
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What is the average ejection fraction(EF)?
Normal is 50-70%
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What are symptoms of a patient having an ejection fraction <50?
SOB, fatigue, chest pain, can't complete ADL's
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What is cardiac reserve?
the ability of the heart to respond to the bodies changing needs. ex tri-athletes and low heart rate but good sv
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What does digoxin do?
Slows the heart rate
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What is cardiac output adjusted to the patient's body size or body surface are (BSA)?
Cardiac Index
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The amount of blood in the ventricle right before ventricular contraction is?
End diastolic volume EDV
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What is the amount of blood left in the ventricle right after ventricular contraction
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At how many beats per minute will you have decreased ventricular filling?
>150 bpm
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Define preload
Amount of fluid minus the amount of cardiac muscle fiber tension, or stretch, that exists at the end of diastole, just before the contraction of the ventricle
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What's important to know about preload and starlings law of the heart?
Its like a rubber band, over time(if too much fluid is given) the stretchiness wears out. The goal of patients in heart failure is to decrease preload.
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What increases preload?
too much iv fluid, renal failure, congestive heart failure (results if Na+ & water retention, electrolyte imbalance, vasoconstriction,
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What are some things that decrease preload?
diuretics, blood loss (hemorrhage), fluid restrictions.
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negative effects of decreased preload?
decreased preload reduces SV and ultimately CO. Decreased preload may be caused from hemorrhage or misdistribution of bold volume such as in third spacing
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Define Afterload
the force that the ventricles must overcome to eject their blood volume into the pulmonary artery and aorta (BP)
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The right ventricle generating enough tension to open the pulmonary valve and eject its volume into the low-pressure pulmonary arteries, measured as pulmonary vascular resistance(PVR)
afterload
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calcium channel blockers do what?
decrease HR and BP
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Beta blockers do what?
Decrease BP and block the effects of epinephrine and adrenaline
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Which node is located in the right atrial and sets the pace for the heart as a whole, or the pace maker of the heart
SA node sinoartial atrial node
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Which node is located directly above the tricuspid valve?
The AV node atrioventricular node
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At what pace will the AV node pace the heart if the SA node fails?
40-60 bpm
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what is the only electrical connection between the ratio and ventricles?
the atrioventricular bundle or the bundle of HIS
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If SA node and AV node what will pace the hear and at what rate?
Perkinje fibers will pace the heart at 20-40 bpm
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What is electrical activity but no actual mechanical muscle contractions called?
Pulseless Electrical Activity
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