Heart Failure Flashcards
What re secondary and principle causes of heart failure?
Hypertension: hypertrophy increasing cardiac work
Ischaemic heart disease: impaired muscle function
Cardiomyopathies (alcohol, viral)
What might heart failure be precipitated by?
Pregnancy Anaemia Hyper + hypothyroidism Fluid retaining drugs: glucocorticoids NSAIDs
What neurohormonal adaption occurs in heart failure?
Sympathetic nervous system
RAAS (renin-angiotensin-aldosterone system)
ADH (anti diuretic hormone)
ANP (atrial natriuretic peptide) to promote sodium loss
What does neurohormonal adaptation lead to?
Increased afterload
Increased circulating volume (increased preload+afterload)
Increased resistance will lead to impaired renal function, more salt/water retention with further activation of RAAS
Myocyte dysfunction
What’s left-sided failure?
Often secondary hypertension
Left ventricle impaired (poor output) leads to increase in left atrial/pulmonary venous pressure with pulmonary oedema
What is right-sided failure often due to?
Lung disease (cor pulmonate) Pulmonary valvular stenosis
What’s biventricular failure?
Both chambers affected
Disease (IHD) has affected both ventricles
Left ventricular failure, leads to pulmonary congestion, may lead to right ventricular failure
What are the signs and symptoms of heart failure?
Fatigue, listless Poor exercise tolerance (determines grade) Cold peripheries Low blood pressure Reduced urine flow Weight loss
What are the symptoms of left ventricular failure?
Pulmonary oedema Dyspnoea Cough? Orthopnoea (nocturnal?) Inspiratory crepitations on auscultation
What are the symptoms of right ventricular failure?
Raised venous pressure
Increased JVP
Enlarged liver
Oedema- ankles, if lying down rises to thighs/abdomen
How is heart failure diagnosed?
Confirmed by echo- ejection fraction <45%
BNP levels (chronic heart failure)
CXR- cardiomegaly, pulmonary oedema, Kerley’s lines (due to sympathetic distension)
What is atrial fibrillation?
LV/valve failure leading to increased pressure in left atrium, leading to distension which leads to AF
What can AF cause?
Stasis of blood and stagnation leading to thrombi which may dislodge and move to cerebral circulation (risk of transient ischaemic attack TIA)
What do you need prophylaxis against in AF?
Thromboembolism
Warfarin or aspirin
What are goals of treatment for heart failure?
Identify/treat any cause (valvular disease/IHD)
Reduce cardiac workload
Increase cardiac output
Counteract maladaption
Relieve symptoms
Prolong quality life- reduce hospitalisation
Which patients should receive an ACEI?
All patients with left ventricular systolic dysfunction
What is used first line in moderate/stable heart failure?
Beta-blockers
What do ACEIs do?
Reduce arterial and venous vasoconstriction
Reduce after and pre-load
Reduce salt/water retention
Inhibit RAAS and so oppose neurohormonal adaptation and may prevent cardiac remodelling
What should you do when treating with ACEI?
Low dose then titrate upwards- may exceed licensed max dose
Do not use with NSAIDs
Monitor urea/creatine and K+ before and during treatment
Avoid in hypotension- systolic <100mmHg
What side effects do ACEIs cause?
Severe hypotension- withdraw diuretic therapy for a few days before; give at night
May cause deterioration of renal function in pre-existing renal disease
When are diuretics used?
Mainstay of therapy
Thiazides- used in mild failure or in the elderly
Loop diuretics (furosemide) especially in pulmonary oedema (iv given for rapid relief)
What do diuretics cause?
Cause reduction in circulating volume, reduce preload and afterload
Also cause venodilatation, reduce preload
What can thiazides/loop diuretics cause?
Hypokalaemia
Less of a problem if they are used with ACEIs
What are the common b-blockers used in heart failure?
Metoprolol
Bisoprolol
Carvedilol (also an a-blocker/antioxidant)
Nebivolol
What do b-blockers do?
Reduce sympathetic stimulation, heart rate and oxygen consumption
Antiarrhythmic activity reduces sudden death
Oppose the neurohormonal activation which leads to myocyte dysfunction
Especially useful un failure associated with ischaemia
What do you need to be careful of when treating with b-blockers?
Start with a low dose under supervision and then work up
Symptoms may get worse at 1st
May be appropriate in concurrent COPD if used with caution
What is spironolactone?
Aldosterone receptor antagonist
Used as an effective agent which reverses the left ventricular hypertrophy
Low dose 25mg reduces mortality 35%
Inhibits effects of aldosterone on the heart- fibrosis which stiffens the heart
What is digoxin?
Positive inotrope by inhibiting Na/K ATPase
Na accumulates in myocytes, exchanged with Ca leading to increased contractility
Impairs atrioventricular conduction and increases vagal activity (via CNS)
The heart block and bradycardia is beneficial in heart failure with AF
What is digoxin contra-indicted in?
Concurrent heart block
Bradycardia
What is digoxin reserved for?
Heart failure with AF
When other treatments fail to control the treatment
How should you give digoxin?
Titrate dose to ensure ventricular rate does not fall below 60 beats/min as this indicates toxicity
How is digoxin affected in renal impairment?
Dose of digoxin is reduced as it’s 2/3rds renal excreted
What should you do with ACEIs and renal function?
Used in care in mild-moderate failure and renal function is monitored
Contraindicated in renovascular disease (renal artery stenosis, when blood pressure and renal perfusion are maintained by high levels of renin)
Why should you monitor potassium?
Hypokalaemia
Side effect of thiazides/loop diuretics
Enhances the effects of digoxin
Possibility of hyperkalaemia with ACEI if used with a K+ sparing diuretic
What are the problems caused by digoxin toxicity?
Narrow therapeutic window
Anorexia, nausea (dose too high), visual disturbances, diarrhoea
Digoxin in AF, monitor pulse (>60bpm)
How should you treat LV dysfunction?
ACEI/b-blocker
Use ATRA if cough
Aldosgterone antagonist or ATRA or hydralazine plus nitrate if persistent symptoms
Then use digoxin
Which drug should be avoided in heart failure?
Rate-limiting calcium channel inhibitors
Decrease cardiac activity and worsen heart failure
DHPs are considered safe
What is used first line when there’s a reduced ejection fraction?
ACEI
When is it best to take furosemide?
In the morning so that diuresis occurs during the day
Why is verapamil contra-indicated in CHF?
Negative inotropic effects can worsen CHF
