Term
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Definition
| a complex syndrome that can result from any structural or functional disorder that impairs the ability of the heart to function as a pump to support a physiological circulation |
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Term
| What are some common causes of HF? |
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Definition
- ischaemic heart disease (CAD)
- cardiomyopathy
- hypertension |
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Term
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Definition
- shortness of breath (dyspnoea)
- swelling of the legs (oedema)
- exercise intolerance
- fatigue |
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Term
| What are 5 tell-tale signs of HF? |
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Definition
1. pulmonary oedema
2. peripheral oedema
3. ascites
4. hepatomegaly
5. raised jugular venous pressure |
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Term
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Definition
| the gastroeneterological term for the accumulation of fluid in the peritoneal cavity |
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Term
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Definition
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Term
| What is the pattern of the NYHA classification? |
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Definition
1 = no limitations of phys activity, no normal activity
4 = severe of phys activity, symptoms at rest |
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Term
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Definition
maintained HF that is subdivided on basis of dominant feature
systolic vs diastolic
left vs right side
congested |
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Term
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Definition
large dilated heart with impaired systolic performance
decreased ejection fraction (less than 45%) |
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Term
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Definition
| impaired diastolic filling (stiffness) |
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Term
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Definition
| when impaired ventricular systolic function is present, this causes pooling of the blood in the periphery, which would normally be received by the RV |
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Term
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Definition
| accumulation of fluid in the pulmonary circulation; much more common than right-sided heart failure but progresses to right sided heart failure |
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Term
| What are the aims of HF treatment? |
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Definition
- relieve symptoms
- improve exercise tolerance
- reduce mortality
NO CURE |
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Term
| What forms the basis of most HF treatment? |
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Definition
primary malfunction leads to maladaptive secondary chnages.
treatment corrects these changes
however, some treatments do work by improving contractility of the heart |
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Term
| Briefly state the autonomic dysfunctions and what they lead to |
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Definition
- increased sympathetic activity
- decreased parasympathetic activity
leads to vasoconstriction -> increases afterload |
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Term
| What does increased sympathetic activity cause? |
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Definition
- increased force of contraction
- increased heart rate
- repolarisation and restoration of function following generalised cardiac depolarisation
- reduced cardiac efficiency (O2 consumption is increased more than cardiac work) |
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Term
| What does decreased parasympathetic activity cause? |
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Definition
- cardiac slowing and reduced automaticity
- inhibtion of AV conduction |
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Term
| Briefly state the neurohumoral dysfunctions and what they lead to |
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Definition
- renin-angiotensin system
- vasopressin
- aldosterone
- endothelin
leads to vasoconstriction, salt retention therefore fluid retention and increased preload |
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Term
| What receptors do large coronary vessels posses? |
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Definition
| alpha-adrenoceptors that mediate vasocontriction |
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Term
| What receptors do smaller coronary vessels posses? |
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Definition
| beta2-adrenoceptors that have dilatory effect |
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Term
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Definition
| the pressure against which the heart has to pump (arterial pressure) |
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Term
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Definition
| the amount the ventricle is stretched by at the end of diastole (EDV) |
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Term
| How is the renin-angiotensin system linked to sympathetic stimulation? |
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Definition
1. increased noradrenaline from sympathetic NS
2. stimulates aldosterone secretion (enhances Na+ reabsorption) |
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Term
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Definition
ADH
antidiuretic
power vasoconstrictor in skin and other vascular beds |
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Term
| What do V1 receptors mediate? |
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Definition
vasoconstriction
requires higher ADH levels
activates PLC |
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Term
| What do V2 receptors mediate? |
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Definition
water retention
requires lower levels
activates adenylate cyclase |
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Term
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Definition
vasoconstrictors
vasodilation (long lived) |
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Term
| What are the structural changes in HF? |
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Definition
myocytes : hypertrophy
cardiac muscle : increased deposition of ECM components such as collagen
blood vessel : changes in endothelial function |
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Term
What are the effects of reducing preload (with HF treatment)?
LOOK AT DIAGRAMS |
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Definition
1. fluid retention decreases
2. preload decreases
3. pulmonary oedema decreases
4. gas exchange increases |
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Term
What are the reducing of reducing afterload (with HF treatment)?
LOOK AT DIAGRAMS |
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Definition
1. vasodilation occurs
2. afterload decreases
3. impedance to output of LV decreases
4. cardiac output increases |
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Term
| What are the 5 treatments for HF? |
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Definition
1. beta blockers
2. ACE inhibitors
3. Diuretics
4. Cardiac glycosides
5. vasodilators
these treatments are usually used in combination |
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Term
| Why is the use of beta blockers in HF paradoxical? |
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Definition
they slow the HR and reduce contractility, thus reducing the heart's ability to function as a pump.
but we want to increase CO |
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Term
| How a change in preload affect SV? |
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Definition
| in a CHF patient, preload changes has little effect on SV therefore causes congestion when pressure (ventricular) is so high |
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Term
| How a change in afterload affect SV? |
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Definition
| in a CHF patient, SV is reduced dramatically as aortic pressure increases until SV is low it causes low output symptoms |
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Term
| What is the outcome if ventricular filling pressure is high on the L-side? |
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Definition
- left side receives blood from the lungs
- congestion on this side
- therefore congestion on the lungs |
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Term
| What are the beneficial effects of beta blockers? |
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Definition
- inhibition of central sympathetic outflow
- direct vasodilation
- prevention of remodelling (hypertrophy or fibrosis)
- reduced dysrhythmias |
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Term
| Describe first gen beta blockers |
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Definition
| non selective (binds to beta 1 and 2) eg propranolol |
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Term
| Describe second gen beta blockers |
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Definition
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Term
| Describe third gen beta blockers |
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Definition
| selective or non selective with additional desirable effects eg carvedilol |
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Term
| what does alpha receptor stimulation cause? |
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Definition
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Term
| what does beta receptor stimulation cause? |
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Definition
vasodilation
therefore beta blockers cause vasoconstriction |
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Term
| Describe the effects of carvedilol |
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Definition
| causes vasodilation via alpha receptors block |
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Term
| What are the adverse effects of beta blockers |
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Definition
- bronchoconstriction (asthma)
- cold extremities
- fatigues
- sleep disturbances (propranolol) |
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Term
| Describe the Angiotensin system |
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Definition
In low BP
1. angiotensin is converted into active form angiotensin I via renin
2. ACE converts angiotensin I to angiotensin II
3. Angiotensin II causes vasoconstriction, fluid retention and aldosterone release |
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Term
| How is the RAS activated? |
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Definition
mechanoreceptors detect:
- decreased SV
- decreased BP
- decreased perfusion rate |
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Term
| Give ACE inhibitor example |
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Definition
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Term
| Adverse ACE inhibitor effects |
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Definition
- hypotension
- hyperkalaemia -> dysrhythmia
- avoided in patients with impaired kidney function
- cough |
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Term
| When are AT1 receptor blockers used? |
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Definition
instead of or in conjunction with ACE inhibitors
block vasoconstriction and fluid retention
they produce a more complete blockade of RAS than ACEI alone
LOSARTAN |
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Term
| What are the benefits of using AT1 alone? |
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Definition
| selective blockage of AT1 receptor preserves potentially beneficial effects of AT2 receptor stimulation |
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Term
| What are the adverse effects of AT1 receptor blockers? |
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Definition
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Term
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Definition
| drugs that increase the rate of urinary excretion and consequently reduce symptoms of oedema and improve exercise capacity |
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Term
| How do diuretics achieve this? |
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Definition
increase salt and water excretion
decrease EDV |
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Term
| How are diuretics classified? |
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Definition
| where they act within the kidney and their potency |
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Term
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Definition
most potent
act on the loop
eg furosemide
for severe congestion |
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Term
| Describe distal tubule diuretics |
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Definition
non K+ sparing = chlorothiazide
K+ sparing = amiloride
mild oedema |
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Term
| Adverse effects of diuretics |
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Definition
volume depletion (hypoperfusion, dehydration postural hypotension)
hypokalaemia
hyperkalaemia |
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Term
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Definition
| a significantly low level of perfusion |
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Term
| Define postural hypotension |
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Definition
| blood pressure suddenly falls when standing up or stretching |
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Term
| Example of cardiac glycoside |
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Definition
digoxin
- reduces symptoms, improves exercise tolerance but does not increase survival |
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Term
| What are the effects of cardiac glycoside |
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Definition
1. increase force of contraction
2. decrease sympathetic drive |
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Term
| Describe how cardiac glycosides increase force of contraction |
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Definition
1. inhibit NaKATPase (which normally removes Na from the cell)
2. Increase [Na]i
3. Na/Ca exchange
4. Increase [Ca2+]i
5. increased contraction |
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Term
| Describe how cardiac glycosides decrease sympathetic drive |
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Definition
1. sensitisation of high pressure baroreceptors
2. reduces central sympathetic flow |
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Term
| Which vasodilators are there? what do they do |
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Definition
Nitrates (isosorbide dinitrate) and hydralazine
decrease ventricular preload and afterload |
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Term
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Definition
| NO donors which cause vasodilation |
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Term
| How does hydralazine work? |
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Definition
| reduces [Ca2+]i and may be an antioxidant |
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