Part 25: Heart Failure Flashcards by AFD Alvarez

at the most fundamental level, what causes heart failure?

progressive damage to the heart that results in reduced cardiac output

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reduced CO that is seen in heart failure can present as ____

weakness, fatigue

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why does reduced CO in heart failure present as weakness and fatigue?

the body is getting less oxygenated blood to the tissues

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the complexity of heart failure comes from what happens when the body tries to ____

compensate and correct for the decreased CO

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define cardiac output (CO)

amount of blood pumped per heart beat (stroke volume) x # of heart beats per minute (HR)

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to compensate for decreased CO, the ____ nervous system is activated

sympathetic

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how does sypathetic activation act to compensate for the decreased CO of heart failure?

NT stimulates B1 receptors in the heart, causing increased heart rate and contractility and increasing renin secretion to increase water retention

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why cant we rely solely on our endogenous compensatory mechanisms for treatment of heart failure?

can only be used short term, for example during exercise and heart failure needs chronic attention. If the compensatory mechanisms tried to do this alone, it would lead to damage (remodelling) and the fluid retention may cause edema and difficulty breathing

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what are the 3 primary management strategies for managing heart failure?

reduce symptoms
decrease progressive damage and remodelling of the heart
if cardiac output is significantly impaired, adding agents to increase CO

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what are the main underlying causes of heart failure?

hypertension and coronary artery disease

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in what part of the heart is heart failure most common and why?

the left ventricle bc it does the most work moving blood out into circulation

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what is congestive heart failure?

umbrella term for any type of heart failure that has a fluid or congestion component

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what does the “congestive” part of congestive heart failure mean?

refers to the accumulation of fluid and edema caused by the failing heart

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left sided heart failure means

left ventricular failure to fill and pump blood into circulation

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left sided hart failure may cause accumulation of fluid in the ____, which is called ____ and is due to ____

lungs; pulmonary edema; blood backing up i the lungs

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right sided heart failure means

right ventricular failure to fill and pump blood to the lungs

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right sided HF may cause fluid accumulation in the ___, called ___, due to ___

peripheries; peripheral edema; blood backing up into the veins

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t/f failure of one ventricle will often progress to the failure of both

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is the pumping action of the heart is reduced, this is called ___ heart failure

systolic

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the capacity of the heart to pump blood out of the ventricles is measured by the ____ (the % of the blood pushed out of the chamber during contraction)

ejiection fraction

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normally, ____% of the blood in the ventricle is pushed out during systole

50-70%

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in systolic failure, the contraction of the ventricles pushes ___(more/less) blood out of the chamber, leaving ____ (more/less) behind

less; more

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in systolic failure, the ejection fraction / proportion of blood pumped out with each contraction is ____ (increased/decreased)

decreased

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a diagnosis of HF is usually made when ejection fraction falls below ___%, but patients in the ____% range can be considered borderline and may experience symptoms of HF with exertion

40; 40-50

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systolic HF is more commonly called ___

HF-rEF: heart failure with reduced ejection fraction

____ HF occurs when stiffening of the ventricular walls prevents the chambers from filling to their normal capacity

diastolic

in what type of HF is there less blood in the chamber before contraction, so less blood is pumped to circulation (reduced CO)

diastolic HF

is the EF always reduced in diastolic HF?

what is the other name for diastolic HF?

HF pEF: HF with preserved ejection fraction

HF pEF can occur bc despite the volume being reduced, the ____ remains within the normal range

proportion

in HF pEF, why is increasing the contractility of the heart is less likely to improve CO?

the contracting of the heart isnt as much of an issue in this type of HF

in HF pef, reduced ____impairs the filling of the ventricles

stretch of the cardiac muscle

the _____ uses a roman numeral system to characterize HF from class I-IV

New York Heart Association

the New York Heart Association bases the classification of heart failure based on ____

the activity level that causes symptoms like dyspnea, heart palpitations, fatigue etc.

what are the 4 classifications of the New York Heart Association?

I: no symptoms with regular activity, symptoms may develop with high activity ii: symptoms with regular activity iii: symptoms with less than regular activity iv: symptoms at rest or minimal activity

what type of classification system is used by the American College of Cardiology?

stages A to D

how does the ACC group HF into the A to D stages?

uses a combination of risk factors, structural information about the heart and symptoms

what structural features would be examined for the ACC classification of HF?

ischemic damage from a previous heart attack, cardiac remodeling such as hypertrophy (enlarged heart), abnormal electrial activity (electrocardiography)

what are the 2 pre-HF stages from the ACC classification?

A and B

what is the benefit of early detection of class A and B HF?

early treatment can delay the progression of HF and significantly impact the QOL

describe the A-D classifications of HF from ACC

A: pre-HF, no symptoms or structural features, but they have risk factors B: pre-HF, structural features (hypertrophy, past MI), but no symptoms C: structural & symptomatic HF D: advanced symptomatic HF despite pharm interventions

which classes of antihypertensives are best for the fluid retention and edema associated with HF?

diuretics, ACE inhibitors, ARBs

give an example of a ARB + neprilysin inhibitor (ANRI) drug used for HF

valsartan/sacubitril

give 2 examples of positive ionotropic drugs

dobutamine and digoxin

for pts requiring extensive diuresis and excretion of large volumes of fluid, what is the best type of diuretic to use?

a loop diuretic like furosemide (the HCTZ loop diuretic may cause hypokalemia, so be careful)

in some cases _____ can be added with furosemide to retain K and aide in diuresis by blocking the actions of aldoesterone in the collecting duct

spironolactone

____ and ____ type drugs are also commonly used in HF as they have multiple beneficial actions reducing fluid retention and lowering BP

ACE inhibitors and angiotensin receptor blockers

t/f the ARB/ANRI combination have been shown to have benefit in HF in comparison to an ACE inhibitor or ARB alone

____ are endogenous hormones that counter balance the actions of the renin-angiotensin system

natriuretic peptides

the natriuretic peptides promote ____ (vasodilation/constriction) and _____ (fluid retention/diuresis)

vasodilation; diureses

what is neprilysin?

endogenous enzyme primarily responsible for the breakdown of natriuretic peptides, bradykinin and angiotensin

why is it important to add an ARB with an ANRI?

bc blocking the natriuretic peptide (by the ANRI) can also increase levels of angiotensin 2, which could cause vasoconstriction, so we add the ARB to inhibit the A2 so that we have a vasodilatlry effect

t/f the ARB/ANRI combo is not used as much bc its newer and most patients are trialed on older ones with more info

HF patient with additional CVD like angina may benefit from the addition of _____ class drug

Ca channel blocker

what class of drug is typically used for the chronic treatment of HF?

a sympatholytic agent like careviol that acts on beta and alpha

beta-blockers can slow the progression of HF and reduce cardiac ___-

remodelling

in what HF scenarios may the use of B blockers not be appropriate?

can further educe CO so not good for pts with an acute exacerbation of HF or those with very low CO

when a patient has very low CO, what class of drugs is a good choice for managing heart failure?

positive inotropic drugs

what is dobutamine?

a + inotropic selective B1 agonist

what is the effect of dobutamine on intracellular Ca, contraction, heart rate and CO

increase all of them

why is dobutamine not used long term?

activates B1, which results in long term remodelling of the heart and progression of heart failure

what are some acute situations where dobutamine may be used?

typically in hospital; surgery, cardiogenic shock, cardiac arrest

very low CO may be called ___

cardiac decomposition

what is an ADR of dobutamine?

arrhythmias

t/f digoxin is a + inotropic drug that can be used chronically for HF to increase CO

in what stage of HF is digoxin used?

advanced

digoxin belongs to a group of compounds called ____

cardiac glycosides

what is the only cardiac glycoside that is used clinically?

digoxin

digoxin and related compounds were originally isolated from plants of the ____ genus

Digitalis

why are digitalis natural remedies not commonly used anymore?

high toxicity and narrow therapeutic range

digoxin ____(increase/decrease) cardiac contractility and ____ (slows/raises) hear rate

increases; slows

digoxin is used in what stage of HF?

advanved stages that have not been responsive to other thinsg

the digitalis plant that digoxin comes from is also called ____

fox glove

what is an ADR of digoxin?

arrrhythmias

what is the MOA of digoxin?

inhibits the Na/K pump in cardiac muscle cells

in the ventricular myocytes, digoxin blocks the Na/K pump causes an accumulation of ____ in the cell which is exchanged for ____ by the ____ exchanger

Na; Ca; NCX

bc digoxin blocks the Na/K pump it makes it ____ (harder/easier) to remove the Na from the cell after an action potential to return to resting state

harder

how can digoxin result in larger ventricylar contraction?

bc the Na/K pump is blocked, the NCX gets used more, so more Ca comes in and gets put in SR storage that will cause a greater release of Ca the next time = greater contraction

how can digoxin cause arrhythmias at very high doses?

so much Na and Ca accumulates in the cell that the resting potential is depolarized in comparison to the control and the SR is so full of Ca that it spontaneously spits ou t Ca causing the uncoordinated contractions that cause arrhythmias

the SA node sets the HR by spontaneously firing APs and sending them to the ____ for propogation to the ventricles to cause contraction

AV node

the rate of SA node firing and AV conduction of the APs is modulated by the ____ nervous system

autonomic

digoxin reduced HR by ___

slowing the propogation of AP in cardiac tissues

the effect of digoxin slowing heart rate are also called ___

parasympathomimetic or vagomimetic

digoxin slows HR by increasing Ca, which prolngs the ____ of electrical conduction in the heart

refractory period