Heart Failure Flashcards
(194 cards)
What is heart failure?
abnormal heart function
-any cardiac structural or functional disorder leading to inadequate CO &/or elevated ventricular filling pressures
-impairs the ability of the ventricles to fill (diastolic) with or eject (systolic) blood
complex clinical syndrome with signs and symptoms of:
-reduced CO and/or unable to meet metabolic demands or only able to maintain CO with abnormally high cardiac pressure
-pulmonary or systemic congestion at rest or with stress
Briefly describe the epidemiology of heart failure.
100,000 Canadians diagnosed each year
700,000+ living with HF in Canada today
higher mortality rates than certain cancers
50% will die within 5yrs
True or false: HF prognosis is worse than many cancers
true
What is a strong predictor of mortality for heart failure?
number of HF hospitalizations
-with each acute event, myocardial injury may contribute to progressive LV dysfunction
What is the pathophysiology of heart failure?
cardiac output is decreased
-persistent=long term activation of compensatory responses
myocardial injury–>compensatory responses in an attempt to maintain CO
How is heart rate controlled?
by the autonomic nervous system
What is stroke volume?
the volume of blood ejected per heartbeat, which is dependent on preload, afterload, and contractility
Differentiate preload, contractility, and afterload.
preload:
-stretching of the muscle fibers in the ventricle
-stretching results from blood volume at the end of diastole
contractility:
-inherent ability of the myocardium to contract normally
-influenced by preload (greater stretch=forceful contraction)
afterload:
-pressure that the ventricular muscles must generate to overcome the higher pressure in the aorta to get blood out of the heart
What is the Frank-Startling Law?
ability of the heart to alter the force of contraction based on changes in preload
increased ventricle volume=increased contractility=increased SV
if the heart is overstretched, it loses its ability to return force
-normal: more filling, greater force
-mild-moderate LV dysfunction: more filling, no more force
-severe LV dysfunction: more filling, less force
In general, what does pharmacotherapy target for heart failure?
the neurohormonal model
-NE, ANG II, aldosterone, vasopressin, cytokines
can slow progression, and reduce risk of morbidity & mortality
What are the compensatory responses seen in heart failure due to decreased cardiac output?
increased preload (via Na and water retention)
vasoconstriction
tachycardia & increased contractility (SNS)
ventricular hypertrophy & remodeling
What are the beneficial and detrimental effects of increased preload as a compensatory response in HF?
beneficial effects:
-optimize stroke volume via Frank-Starling mechanism
detrimental effects:
-pulmonary & systemic congestion
What are the beneficial and detrimental effects of vasoconstriction as a compensatory response in HF?
beneficial effects:
-maintain BP during reduced CO
-shunt blood from nonessential organs to brain and heart
detrimental effects:
-increased myocardial oxygen demand
-increased afterload decreases SV
What are the beneficial and detrimental effects of tachycardia & increased contractility as a compensatory response in HF?
beneficial effects:
-maintain CO
detrimental effects:
-increased myocardial oxygen demand
-shortened diastolic filling time
-precipitation of ventricular arrhythmias
What are the beneficial and detrimental effects of increased ventricular hypertrophy & remodeling as a compensatory response in HF?
beneficial effects:
-maintain CO
-reduces myocardial wall stress
-decreases myocardial oxygen demand
detrimental effects:
-increased risk of myocardial cell death
-myocardial ischemia
-arrhythmia
-fibrosis
-diastolic &/or systolic dysfunction
What are the common etiologies for heart failure?
tachyarrhythmia
valve disease
known or risk factors for CAD
LVH
Describe the universal definition for heart failure.
symptoms and/or signs of HF caused by structural and/or functional cardiac abnormality
-structural heart disease: LVH, valvular heart disease
-abnormal cardiac function: reduced left/right ventricular systolic function, increase filling pressures, abnormal diastolic function
elevated natriuretic peptide levels
-NT proBNP >125pg/ml
-BNP >50pg/ml
objective evidence of cardiogenic pulmonary or systemic congestion
-diagnostic modalities or hemodynamic measurements
What are the typical symptoms of heart failure?
breathlessness
orthopnea
paroxysmal nocturnal dyspnea
reduced exercise tolerance
fatigue
ankle swelling
What are some of the less typical symptoms of heart failure?
nocturnal cough
wheezing
bloated feeling
loss of appetite
syncope
What are the gold standard biomarkers in heart failure?
B-type natriuretic peptide (BNP)
NT proBNP
Where and when would the natriuretic peptides be produced?
synthesized & released from the ventricle in response to pressure or volume overload
What occurs when plasma concentrations of natriuretic peptides are elevated?
increased natriuresis, diuresis & attenuate RAAS & SNS activation
Can the natriuretic peptides alone be used to diagnose heart failure?
good for ruling out HF, not to establish HF on its own
should not be used independent of signs/symptoms & other diagnostics
Which natriuretic peptide is used for heart failure?
either can be used (similar)
-dependent on local lab
absolute values & thresholds are not interchangeable