Heart Failure Flashcards
Define heart failure:
inability of the heart to meet the metabolic needs of the body
Is heart failure the same as cardiac dysfunction?
No it is not
Why is clinical diagnosis of heart failure so difficult?
There is no one single finding that is definitive
What are the two main causes of heart failure?
Decreased circulatory supply and increased circulatory demand
Give some examples of decreased circulatory supply
Coronary Heart disease, Valvular heart disease, cardiomyothay
Give some examples of increased circulatory demand
hypertension, thyrotoxicosis, anemia, A-V fistula
Name the three adaptation mechanisms and when they are used:
Frank- starling (short term)
Neuro-hormonal (intermediate
Hypertrophy (long term)
In heart disease, when ventricular EDV is increased, does ventricularn performance also increase? (hint: frank- starling mechanism)
No, it does not
Why does pulmonary edema commonly occur with heart failure?
It is a common symptom because the LV filling pressure increases to at or above a critical point (25 mmHg) where the oncotic pressure of the plasma pressure is exceeded. This leads to fluid crossing the alveolar membrane.
What are the different mechanisms that result in increased sympathetic stimulation (increased plasma NE)?
1- increased release by neurohumoral endings
2- increased uptake by neurohumoral endings
3- decreased rate of NT degredation
4- beta 1 receptor exhaustion
5- decreased beta 1 receptor synthesis
6- increased coronary sinus NE output
What is plasma norepinephrine an estimate of?
It is an estimate of sympathetic stimulation
What is increasing levels of plasma norepinephrine associated with?
It is associated with decreasing length of survival in heart failure
In heart failure, blood flow is maintained to brain and heart during exercise at the expense of what?
The skin, skeletal muscles, gut and Kidneys
What is the stimuli for the renal (neurohumoral) adaptive mechanism?
decrease in glomular filtration rate—> decrease in renal blood flow —-> aldosterone
What is the response in the renal (neurohumoral) adaptive mechanism?
increase in Na and H2O reabsorption, increase plasma volume, increase venous return, increase venous pressure
Which beta receptor (1 or 2) is reduced by heart failure?
Beta 1 receptors
What are some of the effects of angiotensin II release?
myocardial hypertrophy, increased NE release, Na+ retention, vessel hypertrophy, increased aldosterone
Are the levels of ANP, endothelin, arginine vasopressin and PNE increased or decreased during heart failure?
They are ALL increased
Where does endothelin come from and what does it do?
It is from endothelial cells and it is a vasoconstrictor
What does ANP promote?
vasodilation
What other molecule has similar mechanism to ANP?
Brain natriuretic factor
What is hypertrophy?
increased in myocardial mass (remodelling)
What happens to the hypertrophy is the abnormality in the heart can be fixed?
it will regress
When does hypertrophy occur?
During pressure and volume overload
What is the definition of ejection fraction?
= (EDV-ESV)/ EDV
Is the muscle increase effective in hypertrophy?
No, the muscle is not as effective, even though there is more of it, because there is a decrease in active tension which leads to a decreased contractability
Does concentric or eccentric hypertrophy lead to elongated sacromeres?
eccentric (they are in series)
What type of hypertrophy does volume overload lead to? What about pressure overload?
eccentric= volume overload
concentric= pressure overload
Is left ventricle thickness greater with pressure or volume overload?
pressure
Is left ventricle volume greater with pressure or volume overload?
volume
What is the h/R ratio greatest in/
pressure overload vessels
What is the disadvantage the the frank starling adaptation?
high left ventricle end diastolic pressure (leads to pulmonary edema)
What are the disadvantages to neuro-humoral adaptation?
1- increased myocardial O2 consumption
2- arrhythmias
3- deminished response to sympathetic stimulation
4- blunted baroreceptor function
5- increased systemic vascular resistance
What are the disadvantages to renal adaptation?
1- peripheral/ organ edema
2-decreased renal function
What are the disadvantages of myocardial hypertrophy/ remodeling adaptation?
1- decreased contractability
2- necrosis and apoptosis
3- decreased coronary reserve
4- changes in matrix
What is adaptive mechanism failure characterized by?
worsening LV function, fluid retention (pulmonary edema), excessive increase in vascular resistance, renal failure
What characterized right heart failure?
pulmonary embolism, cor pulmonale, mitral stenosis
What a characterizes left heart failure?
mitral insufficiency, aortic stenosis and insufficiency, hypertension, cardiomyopathy
What is characteristic of acute CHF?
myocardial infarction and endocarditis
What is characteristic of chronic CHF?
cardiomyopathy, hypertension
What is characteristic of low cardiac output?
cardiomyopathy and coronary heart disease
What is characteristic of high cardiac output?
Thyrotoxicosis, anemia, and AV fistula
What is forward heart failure an effect of?
Low cardiac output
What is characteristic of diastolic heart failure?
delayed relaxation and increased stiffness (rare)
What is a good agent to treat diastolic heart failure?
Aldosterone antagonists
What are some treatment options for CHF?
1- treat underlying cause 2- ionotropic agents 3- diuretics 4- venodilator 5- arterial vasodilation 6- beta blockers 7-aldosterone antagonists 8- LVAD 9- transplant 10- internal defibrillator
