Chronic Heart Failure Flashcards
Define Heart Failure
Failure of the heart as a pump to meet the circulatory needs
What are the two components of the heart that may fail?
Heart Muscle
Heart Valves
What are the two main classifications of Heart Failure?
Chronic
Acute
What are the most common causes of Heart Failure?
Hypertension (hypertrophy, increased cardiac work)
IHD (impaired muscle)
Cardiomyopathies (alcohol, viral)
What factors may precipitate Heart Failure?
Pregnancy
Anaemia
Hyper-/Hypo-thyroidism
Fluid retaining drugs (NSAIDs, glucocorticoids)
What are the four neurohormonal responses as a compensation for circulatory failure?
Activation of SNS
Activation of RAAS
Activation of ADH (Anti Diuretic Hormone)
Activation of ANP (Atrial Natriuretic Protein)
What are the effects of neurohormonal adaptation?
Increased afterload
Increased circulating volume
Increased resistance - impaired renal func - salt/water retention - activation of RAAS
MYOCYTE DYSFUNCTION
Describe Left-Sided Heart Failure
Impairment of LV (poor output) leading to increased LA/pulmonary venous pressure (pulmonary oedema)
Secondary to hypertension
Describe Right-Sided Heart Failure
Impairment of RV (poor output) leading to increased RA pressure
Secondary to lung disease (cor pulmonale) or pulmonary valvular stenosis
Describe Biventricular Failure
Impairment of both chambers
Can be due to IHD of both ventricles
LVF leads to pulmonary congestion, can lead to RVF
What are the signs/symptoms of Heart Failure?
Fatigue Poor exercise tolerance (grading) Cold peripheries Low BP Reduced urine Weight loss
What signs/symptoms are specific to LVF?
Pulmonary Oedema
- Dyspnoea w/ sensation of drowning
- Orthopnoea
- Cough
- Inspiratory crepitations
What signs/symptoms are specific to RVF?
Raised venous pressure
Increased JVP
Enlarged liver
Peripheral oedema
What diagnostic signs are needed to confirm a diagnosis of Heart Failure?
Ejection Fraction <45% (echocardiogram)
BNP levels
What signs of Heart Failure are present on a CXR?
Cardiomegaly
Pulmonary oedema
Kerley’s lines (lymphatic distension)
What is Atrial Fibrillation?
A condition where the LA has multiple pacemaker signals
An abnormal heart rate characterised by rapid and irregular beating
What is the most common cause of Atrial Fibrillation?
LV/valve failure - increased LA pressure - distension - Atrial Fibrillation
What is the major risk with Atrial Fibrillation?
Stasis of blood - thrombi formation - risk of TIA
How should Atrial Fibrillation be treated prophylactically?
Prophylaxis against thromboembolism
Warfarin/Aspirin
What are the main goals when treating Heart Failure?
Treat any cause Reduce cardiac workload Increase cardiac output Counteract maladaptation Relieve symptoms Prolong quality life
How is pharmacological management for Heart Failure decided?
Stage dependent
What should patients with Left Ventricular Systolic Dysfunction be treated with?
ACEIs
What should patients with Oedema be treated with?
Diuretics
What should patients with moderate/stable Heart Failure be treated with?
Beta-Blockers
Why are ACEIs effective in LVSD?
Reduce arterial/venous vasocoonstriction
Reduce salt/water retention
Inhibit RAAS system (oppose neurohormonal adaptation)
Give several examples of ACEIs
Ramipril, Lisinopril, Enalapril
How should ACEI dosing be controlled?
Start with a low dose then titrate up
What drug class should ACEIs not be used with?
NSAIDs
What should be monitored before and during treatment with ACEIs?
Urea/Creatinine
K+
When should ACEIs be avoided?
Hypotension (<100mg sys)
Renal failure
What are the most common problems with ACEIs?
Severe hypotension
Cause renal damage
Hyperkalaemia
How do ATRAs work?
Oppose actions of AII at the AT1 receptor
Give examples of ATRAs
Candesartan
Valsartan
Losartan
When are diuretics used to treat Heart Failure?
When oedema is present
What sort of diuretics are used to treat Heart Failure?
Thiazides (bendroflumethiazide) - mild failure/elderly Loop Diuretics (Furosemide) - pulmonary oedema
How do diuretics work?
Reduction in circulating volume
Reduce pre-/after-load
Venodilation
What is the major problem with diuretics?
May cause hypokalaemia
When are Beta-Blockers used to treat Heat Failure?
Stable/moderate failure
Esp. useful when associated with Ischaemia
How do Beta-Blockers work?
Reduce sympathetic stimulation/hear rate/O2 use
Antiarrhythmic
Oppose neurohormonal activation
How should Beta-Blocker dosing be controlled?
Start with low dose and increase
What may be the immediate response to treatment with Beta-Blockers?
Symptoms may get worse at first
What is Spironolactone?
Aldosterone receptor antagonist
How is Spronolactone used?
Reverses left ventricular hypertrophy
Inhibits effects of aldosterone on heart (ie. fibrosis)
What is Digoxin?
Positive inotrope causing heart block and bradycardia
How does Digoxin work?
Inhibits Na+/K+ ATPase
Na accumulates - exchanged with Ca
INCREASED CONTRACTILITY
Impairs AV conduction, increases vagal activity
When is Digoxin used to treat Heart Failure?
Heart failure with atrial fibrillation
How should Digoxin dosing be controlled?
Titrate dose, ensure ventricular rate doesn’t fall below 60BPM
What drugs are contraindicated in renal failure?
Thiazides - ineffective
ACEIs - impair renal function
Why should Potassium be monitored during treatment?
Thiazides/Loop Diuretics cause Hypokalaemia
Enhances effect of Digoxin
ACEIs w/ K+ sparing diuretic causes Hyperkalaemia
Describe Digoxin toxicity?
Narrow therapeutic window
Anorexia, nausea, visual disturbances, diarrhoea
Pulse <60BPM
