Heart Failure Flashcards
What are common causes of heart failure ?
Ischaemic heart disease
Cardiomyopathy
Hypertension
Idiopathic causes seen due to mutations of proteins in cardiac tissue
What is heart failure ?
Complex syndrome that results from any structural or functional disorder which impairs the ability of heart to function as a pump to support physiological circulation
What are the symptoms of heart failure ?
Fatigue
Dyspnoea
Odema
What are the signs of heart failure ?
Pulmonary oedema Peripheral oedema Ascites Liver enlargement Raised jugular venous pressure
What are the subdivisions of chronic hf ?
Systolic- large dilated heart that can’t eject blood properly
Diastolic- impaired filling due to stiffness
Right sided- impaired right ventricular function causing peripheral congestion
Left sided- impaired left ventricular function causing pulmonary congestion
Congestive- symptoms of circulatory congestion
Who is at a greater risk men or women ?
Men
What are the aims of treatment in hf ?
Relieve symptoms
Improve exercise tolerance
Reduce mortality
What do the secondary changes of heart do ?
Try to overcome the primary malfunctions of the heart but they then lead to other problems
What are the 3 maladapatations of hf ?
Autonomic dsyfunction- increase sympathetic drive and decrease para drive
Neurohumoral adaptations - renin angiotensin system, vasopressin and endothelium-1
Structural changess- hyper trophy, fibrosis
What are the maladaptive consequences of hf ?
Vasoconstriction - increases after load
Fluid retention - increases preload
In chf the SV doesn’t increase alongside the increased preload, what effect does this have and what treatments are needed ?
Leads to ventricular filling pressure reaching very high levels causing congestive symptoms
Treatment is to decrease fluid retention so preload is reduced to reduce pulmonary oedema and improve gas exchange
How is the increased after load treated ?
Cause vasodilation to decrease after load so that the CO can increase
What are the beneficial effects of beta- blockers in hf ?
Inhibits sympathetic output
3rd gen causes direct vasodilation
Helps to prevent hyper trophy occurring
Reduces dsyrythmias
Give examples of beta blockers..
1st gen- non selective - propranolol
2nd gen - beta-1 selective - atenolol and bisoprolol
3rd gen- selective or non selective - carvedilol - causes vasodilation by causing NO release
What are the adverse effects of beta blockers ?
Bronchoconstriction
Cold extremities
Fatigue
Sleep disturbance
What happens when angiotensin 2 binds to at-1 receptors?
Causes the maladaptive changes vasoconstriction and fluid retention
What do ACE inhibitors do and examples
Block angiotensin converting enzyme so prevent co version of angiotensin 1 to angiotensin 2 which reduces symptoms and increases exercise tolerance
Captopril and ramipril
What are the adverse effects of ACE inhibitors?
Can lead to hypotension in patients using diuretics
Hyperkalemia
Avoided in patients with renal failure
Cough
What are the effects of at-1 receptor blockers and examples
They block the binding of angiotensin 2 to at-1 receptors which prevents the maladaptive changes
Helps to maintain the beneficial effects of angiotensin 2 at at-2 receptors
Losartan
How do diuretics work ?
Increase rate of urinary excretion
Increase salt and water excretion
Decreases EDV so reduces symptoms of oedema and improves exercise capacity
What are the 2 types of diuretics ?
Loop diuretics - furosemide and bumetanide
- inhibit sodium reabsorption on ascending limb
Non- potassium sparing - chlorothiazide
Potassium sparing- amiloride, spironolactone- aldosterone antagonists
Which duiretic are used when ?
Severe congestion - loop diuretic s
Mild oedema- diuretics that work on distal tubules
What are the adverse effects of diuretics ?
Volume depletion- dehydration
Postural hypotension
Hypokalemia - non potassium sparing
Hyperkalemia - potassium sparing
Why are cardiac glycosides used in hf ?
Rescue symptoms, improve exercise tolerance and reduce hospitalisation.
Acts to improve contractility of he heart
What is the mechanism of action of cardiac glycosides ?
Increase force of contraction - inhibit sodium/potassium ATPase which increase intracellular sodium, by sodium calcium exchange it increases intracellular calcium which increases contraction.
Decrease sympathetic dive by sensitising baroreceptors
How do vasodilators work on hf ?
Nitrates act as NO donors to cause vasodilation
Increase exercise capacity and decreases preload and after load
