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cardiac effects on arterial flow kaye's class

  1. systole is when
    the heart muscle contracts, and it pushes the blood out of the heart and into the large blood vessels of the circulatory system. from here the blood goes to all of the organs and tissues of the body. during systole, a person's blood pressure increases. this is called systolic pressure.
  2. diastole is when
    the heart muscle relaxes between beats, and the chambers refill with blood. during this time, the blood pressure drops. this is called diastolic pressure
  3. End systolic volume ESV is the
    volume of blood in a ventricle at the end of contraction or systole and right before the beginning of filling or diastole. ESV is the lowest volume of blood in the ventricle at any point in the cardiac cycle.
  4. End Diastolic volume EDV is the
    the volume of blood in the right and or left ventricle at the end filling in or the amount of blood in the ventricles just before systole
  5. Cardiac output CO is the
    amount of blood that is pumped out of the heart in one minute. 

    anything that changes either the stroke volume, or the heart rate also changes the cardiac output
  6. the equation for Cardiac output
    CO=SVxHR
  7. at rest on average a healthy heart beats approximately
    75 times a minute.

    approximately 75ml of blood is pumped out with each beat roughly 1/3c.

    multiplying the 75 beats per minute times 75ml of blood pumped by each beat yields an average cardiac output of about 5.6 liters of blood per minute. that's roughly the body's entire blood supply being pumped through the heart each minute.
  8. normal cardiac output is in the range of
    4-8L /min
  9. an average person has a total of about
    5 to 6 liters of blood
  10. stroke volume is the
    amount of blood that is ejected from the left ventricle in one contraction
  11. the equation for stroke volume is
    SV=EDV-ESV
  12. EDV(end diastolic volume) and ESV ( end systolic volume) are not
    independent of each other. any factor that alters either the EDV or the ESV will affect SV. An increase in EDV increases SV because of the increase in pressure
  13. IF contractility is decreased then
    Stroke Volume SV is decreased because it doesn't have enough oomph to squeeze causing ESV to increase
  14. An increase in ESV because maybe the peripheral systemic pressure is too high usually results in an
    increase EDV in order for the heart to compensate, which in turn causes an increase in SV and it is a vicious cycle
  15. preload is
    the load or stretch put on the ventricle by the amount of blood volume that is entering the ventricle.
  16. an increase in preload will
    increase strength/ force of contraction will increase stroke volume
  17. afterload is
    the resistance that the ventricle must pump against in order to eject the stroke volume. It can be thought of as the pressure that the ventricle needs to generate in order to move the blood into the aorta

    -normal hearts can compensate for a certain amount of afterload
  18. for failing hearts increase afterload equals
    decreased strength/force of contraction= decreased stroke volume
  19. contractility is the
    intrinsic strength ability to contract of the ventricle, independent of any loading conditions.

    if nothing else were to change increasing contractility increases stroke volume and decreasing contractility decreases stroke volume
  20. Ejection Fraction (EF) is the
    measurement expressed as a percentage of how much blood the left ventricle pumps out with each contraction. 

    an ejection fraction of 60 percent means that 60 percent of the total amount of blood in the left ventricle is pushed out with each heartbeat
  21. cardiac arrhythmias
    if the arrhythmia is isolated or intermittent and you can get a peak systolic velocity during normal sinus rhythm then it is not a problem as it possible to obtain reliable data
  22. if the arrhythmia is sustained and or severely irregular obtaining a reliable peak systolic velocity
    may not be possible
  23. aortic valve stenosis waveform characteristics
    delay of systolic upstroke

    decrease peak systolic velocities
  24. aoritc valve regurgitation/ insufficiency
    a double systolic peak pulsus bisferiens


    diminished diastolic flow or reversed flow during diastole

    pandiastolic diastolic flow reversal or reversed flow during diastole
  25. severe aortic regurgitation
    significant flow reversal in the proximal aorta of the patient
  26. high cardiac output will
    increase in peak systolic velocities throughout the circulatory system may be normal for younger/ athletic individuals who have no evidence of vessel wall irregularities

    -increase in peak systolic velocities may also be related to a non-cardiac source such as ANEMIA

    -    PSV measurements may overestimate the degree of stenosis in theses cases
  27. low cardiac output with a sharp upstroke are indicative of
    a decreased cardiac output
  28. low cardiac output decreased PSV with rounded upstrokes visualized bilaterally indicative of
    severely reduced ejection fraction such as is typically seen in cases of severe CM
  29. intra-aortic balloon pump
    used in cases of acute MR unstable angina, intra-operative MI, low CO following bypass surgery.

    goal of device is to provide temporary assistance with Left ventricle contraction, by decreasing the force that the left ventricle encounters as it contracts

    produces altered doppler waveforms throughout the circulatory system

    produces lowered peak systolic velocities which may result in an underestimation of stenosis
  30. ventricular assist device
    used for patients in heart failure/awaiting heart transplant
Author
139shay
ID
348559
Card Set
cardiac effects on arterial flow kaye's class
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cardiac effects on arterial flow kaye's class
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