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
• End-diastolic volume (or EDP) is used as an index _____ and is influenced by:
preload
– End-diastolic volume is influenced by chamber compliance
End-systolic volume depends on the______ and
__________, but not on________
afterload and contractilty
not on preload
Heart Failure is a result of a wide variety of CV diseases, those that:
– Impair ventricular contractility
– Increase afterload
– Impair relaxation and filling
What abnormalities could lead to Heart failure
– Emptying, i.e., systolic dysfunction
– Filling, i.e., diastolic dysfunction
How are pts with heart fail categorized?
Heart failure with reduced EF
Heart failure with preserved EF
In heart fail with reduced EF:
Ventricle has diminished capacity to eject blood because of
impaired contractility or pressure overload
Possible causes of reduced EF:
May result from:
– destruction of myocytes
– abnormal myocyte function
– fibrosis
If it’s pressure overload: ejection is impaired by increased resistance to flow
Causes of heart fail with preserved EF
Usually demonstrate abnormalities in diastolic function
– Impaired early relaxation and/or increased stiffness
For instance:
• Acute ischemia
• Hypertrophy
• Fibrosis
• Restrictive
cardiomyopathy
• Pericardial diseases
In right sided heart fail: RV has_____ compliance
These patients are susceptible to failure with a sudden increase in______
high
afterload
Right-sided heart failure that results from a primary pulmonary process is called:
– Cor pulmonale
What tries to maintain forward stroke volume and to maintain perfusion of vital organs in heart fail?
Frank-Starling mechanism and hypertrophy
-issue is chornic increase in EDV (from frank) and left ventricle stiffness (from hypertrophy) will increase atrial pressure
What neurohormal activation occurs in heart fail
increase SNS
activate renin-angiotensin-aldosterone axis
release anti-diuretics
What is the goal of neurohormonal activation in heart fail pts and what are the consequences?
activating SNS/angtiotensin/ADH becuase we try to miaintain perfusion of vital organs via increase CO and maintaning BP
Bad news is w/ chronic activation we get increase in afterload and fluid retention
Long term compensatory mechanisms and neurohormal activaiton in heart fail result in this viscious cycle:
low CO–> increase NE/AII/ET–> will increase Afterload–> which decreases EF which further decreases CO
Clinical manifestations in heart fail pts are precipitated by circumstances that
increase cardiac workload and tip the balance to one of decompensation
What are some precipitating factors in heart fail pts?
increased metabolic demand (fever/anemia/tachy/pregnancy)
increased circulating volume, ie increased preload (renal fail, excess sodium or fluid)
conditions increasing afterload (uncontrolled HTN, pulmonary embolism)
Fail to take prescribed heart fail meds or very slow HR
Symptoms and findings of Left sided heart fail
Dyspnea ,Orthopnea, Paroxysmal nocturnal dyspnea, Fatigue
Diaphoresis (sweating)
Tachycardia, tachypnea
Pulmonary rales
•Loud P2
•S3 gallop (in systolic dysfunction)
• S4 gallop (in diastolic dysfunction)
Symptoms and findings of right sided heart fail
peripheral edema, RUQ discomfort (d/t hepatic enlargement)
jugular venous distention, hepatomegaly, peripheral edema
Loud P2, and S3 gallop or S4 gallop can all be heard in
left sided heart fail
Pt has Cardiac disease, but no limitation in physical activity, what NYHA class is he
Class I mild
Pt has symptoms below, what NYHA class is he?
– Marked limitation of physical activity
– Dyspnea with minimal exertion (i.e., slowly walking up stairs)
– Comfortable only at res
Class III - moderate
Pt has Slight limitation of physical activity and Dyspnea and fatigue with moderate exertion (i.e., walking up stairs quickly, what NYHA class?
Class II: mild
Pt has severe limitation of activity and symptoms are present at rest. what class is she?
Class IV: severe
Prognosis for heart fail
5 year mortality rate of:
If severe symptoms, class III or IV we have
5 year mortality at 45-60%
40% survival of one year if severe
Mortality in heart fail is due to:
refractory heart failure and sudden cardiac death
There is no difference in prognosis in pts with preserved EF or reduced EF
T/F
True
Goals of therapy for Heart fail d/t reduced EF
Correct underlying condition causing heart
failure
• Eliminate acute precipitating cause of symptoms
• Management of heart failure symptoms
– Pulmonary and systemic vascular congestion
– Provide measures to increase forward cardiac output
• Modulation of neurohormonal response
• Prolong survival
• Glycoside derived from plant species
from the genus digitalis (foxglove)
• Only cardiac glycoside available in
the U.S.
• Chemically consists of a steroid
nucleus linked to a lactone ring and a
series of sugars
Digoxin—not used as much anymore in heart fail d/t reduced EF
