CVS 11 Heart Failure Flashcards
Define Heart failure
A state in which the heart fails to maintain adequate circulation for the needs of the body despite an adequate filling pressure
What is the primary cause of systolic heart failure
Ischaemic heart disease
Give some causes of Heart Failure
Hypertension Dilated cardiomyopathy (bugs, alcohol, drugs, poisoning, pregnancy) Valvular heart disease/congenital Restrictive cardiomyopathy e.g. amyloidosis Hypertrophic cardiomyopathy Pericardial disease High output heart failure Arrythmia
What happens to starling’s law in heart failure?
The heart can no longer give the same amount of force/CO for a given level of filling
How does class I heart failure affect physical activity?
Doesnt, no symptomatic limitation
How does class II heart failure affect physical activity?
Slight limitation. Ordinary physical activity gives symptoms but no symptoms at rest
How does class III heart failure affect physical activity?
Marked limitation of physical activity.
Less than ordinary activity results in symptoms
No symptoms at rest
How does class IV heart failure affect physical activity?
Inability to carry out physical activity without symptoms
May have symptoms at rest
Discomfort increases with any degreee of physical activity
When does right sided heart failure occur?
MOST OFTEN SECONDARY TO LEFT HF Chronic lung disease Pulmonary embolism/hypertension Pulmonary/tricuspid valve disease L-R shunts Isolated RV cardiomyopathy
How does left heart failure lead to right heart failure?
Increased pressure in LV due to poor output due to increased afterload leads to increased pulmonary arterial pressure giving right sided heart failure
What are some signs and symptoms of Left sided heart failure?
Fatigue, shortness of breath upon exertion or when lying down Waking up with shortness of breath Tachycardia Cardiomegaly (displaced apex beat) 3rd or 4th heart sound (gallop rhythm) Functional murmur of mitral regurgitation Basal pulmonary crackles Periphery oedema
What are some signs and symptoms of right sided heart failure?
Peripheral oedema in areas drained by systemic veins Fatigue, dyspnoea, anorexia, nausea Raised JVP Tender, smooth hepatic enlargement Pitting oedema Ascites Pleural effusion
What is the RAAS system?
Renin-angiotensin-aldosterone system
When and why is this system activated?
Activated in heart failure when there is a drop in bp to maintain cardiac output (This makes already struggling heart work harder
What stimulates renin release? Where is it released from?
Drop in bp stimulates renin release from the kidneys
What is renin?
An enzyme that catalyses conversion of angiotensin to angiotensin I
What does ACE do?
Angiotensin converting enzyme converts angiotensin I to angiotensin II
What does angiotensin II do?
Powerful vasoconstrictor
Promotes aldosterone release by adrenal gland (zona glomerulosa)
What does aldosterone do?
Increases Na+ and water retention in kidneys, increasing blood volume
What happens to the sympathetic nervous system in heart failure?
Stimulated causing vasoconstriction via a1 receptors increasing blood pressure and workload of the heart via increased preload and afterload
Stimulation of b1 receptors in heart causes increased chronotropy and inotropy
What do ACE inhibitors do?
Prevent angiotensin II production having indirect vasodilatory and diuretic effects and so reducing work load of heart
What drugs are given in heart failure?
ACE inhibitors- vaso dilate reduce bv
Diuretics
Beta-blockers
Ca2+ channel blockers- reduce myocardium contractility
Organic nitrates- veno/vaso dilator, reduce BP
Cardiac glycosides
How do cardiac glycosides work?
Increase contractility and CO by inhibiting Na/K pump raising intracellular Na+ which inhibits NCX increasing intracellular Ca2+
