Heart Failure Flashcards
Heart failure produces a complex of symptoms related to:
inadequate perfusion of tissues and retention of fluid
Most common diagnosis of hospitalized pts aged 65 year and older
heart failure
What ‘state’ is the heart in in heart failure in regards to its ability to pump blood and cardiac filling pressures
heart is unable to pump blood at a rate sufficient to meet the requirements of metabolizing tissues, or is only able to do so only if the cardiac filling pressures are abnormally high (or both)
Three major determinants of stroke volume
– Contractility, preload, afterload
measured as LV end diastolic volume or pressure
preload
cardiac function increases as a function of ______
preload
In hear fail.. pt will increased _____ trying to achieve an increase in SV. This doesn’t happen and instead we end up with______
LVED pressure or volume pulmonary congestion
Resistance the ventricle must overcome to empty its contents – Largely a consequence of aortic pressure
Afterload
Preload is related to: Afterload is related to:
Frank Starling Curve Laplaces law
Afterload rises in response to higher pressure load (hypertension) or increased chamber size (dilated LV)… as a result we see:
– Increases in wall thickness serves a compensatory role to reduce wall stress
Accounts for the changes in myocardial force for a given set of preload and afterload conditions – Influenced by the availability of intracellular Ca
contractility
On a Frank–Starling curve, a change in contractility shifts the curve in an
upward or downward direction
What point on pressure volume loop does the mitral vavle open?
mitral valve close?
Opens at point a = beginning of diastole
Closes at point b
What point represents isovolumetric contraction
isovolumetric relaxation
b-c
d-a
What point represents the aortic valve opening?
closing?
opens at c
closes at d
What curve represents compliance?
a-b
When arterial pressure (afterload) and contractility are held constant, sequential increases (lines 1, 2, 3) in preload (measured in this case as end-diastolic volume [EDV]) are associated with loops that have progressively _______ but a constant ________
(refer to image on left)
higher stroke volumes
end-systolic volume (ESV)
When the preload (EDV) and contractility are held constant, sequential increases (points 1, 2, 3) in arterial pressure (afterload) are associated with loops that have progressively lower _____and higher _______.
(refer to image on right)
stroke volumes
end-systolic volumes
There is a nearly linear relationship between the afterload and ESV, termed the
end-systolic pressure-volume relation (ESPVR)
• If afterload is increased, then pressure generated during ejection increases
Thus more_____ is expended to overcome resistance to eject, and les fiber shortening occurs
work
Relationship between End systolic volume and afterload is approximately
linear
–greater the afterload the higher the end systolic volume
Slope of ESPVR line is fnx of contractility:
with increased contractility the line becomes _______
steeper
When we increase contractility of the heart the ventricle will:
empty more completely… thus we get smaller ESV thus increased SV
Stroke volume is a function of
preload, afterload, and contractility.
– Augmented with increased preload, decreased afterload, or increased contractility
