Lecture 6 First-line Treatment of Heart Failure Flashcards
What are the different treatment pathways for heart failure?
Positive inotropes
Vasodilator drugs
ACE inhibitors
Diuretics
What are the different conditions that lead to heart failure?
Myocardial infarction
Hypertension
Increased preload and after load
Why are the treatments of heart failure used?
To help manage the symptoms of heart failure and to stop the compensation mechanisms
What does a lesser ejection fraction mean?
Means less blood is pumped out of the heart (lower stroke volume)
What are the first-line treatments for heart failure?
ACEI and/or Beta blocker
Mineralocorticoid receptor antagonist if symptoms persist
What is an example of a mineralocorticoid receptor antagonist?
spironolactone
What is the first line of treatment if there are congestive symptoms and fluid retention?
A loop diuretic
What is meant by congestive symptoms in heart failure?
Breathlessness due to fluid backing into the lungs from capillaries
What drugs must be used when there is a risk of thrombosis in heart failure?
Anticoagulant
Why is there a risk of thrombosis in heart failure?
Decreased cardiac output therefore blood stasis leading to clotting
What are the drugs avoided in heart failure?
Verapamil (cardiac calcium channel blocker) - usually used for hypertension or arrhythmias
Why is a calcium channel blocker not used in heart failure?
As there is a lower force of contraction which decreases the stroke volume even more
What are examples of loop diuretics?
furosemide, butmetanide, torasemide
Where are loop diuretics used?
Pulmonary oedema (LV failure)
Chronic heart failure
Increase vasodilator effect (like thiazide drugs)
Adjunct to antihypertensive (resistant only)
How are loop diuretics administered?
Intravenously and orally
What are loop diuretics?
Reduce electrolyte reabsorption in thick ascending limp loop of henle
Promote urinary excretion of Na+, Cl-, K+ and H2O
Highly potent
What are the pharmacokinetics of loop diuretics?
IV - 10min onset
50% oral bioavailability
Peak effect 30 mins
Half like - 2h (lasts 4-6h)
Liver P450 metabolism
Where do loop diuretics work?
In the ascending limb of the loop of henle on the C1 transmembrane protein transporting Na+, K+ and Cl-
What is the difference between loop and thiazide-like diuretics?
Loop have a high ceiling effect therefore they cause a larger volume of urine to excrete
Thiazide-like have a low ceiling effect and most drugs level off at a certain dose
What are the contra-indications of loop diuretics?
Anuria (no urine produced) - kidney failure
Drug induced renal failure
Severe hypokalaemia
Severe hyponatraemia
What are the cations for loop diuretics?
Urinary retention if enlarged prostate
Risk hypovolaemia, hypotension, hypokalaemia (spironolactone)
Lower dose in elderly (dehydration=confusion= falls)
Name some side effects of loop diuretics
Dizziness
Electrolyte imbalance
Fatigue
Headache
Metabolic alkalosis
Nausea
What are the different ACE inhibitors used?
Ramipril, captopril, enalapril
What is an alternative to ACEIs?
ARBs (candesartan, losartan, etc.)
What are the beta blockers used in heart failure?
Bisoprolol, carvedilol, nebivolol
What is the mechanism of beta blockers?
Inhibit beta1 adrenergic receptors
Block Adr and NAdr
Inhibit effect of renin
What is the effect of beta blockers on the heart?
Slower rate of firing of SAN/AV node
What is the effect of beta blockers on cardiac muscle?
Negative inotropic effect
What are the side effects of beta blockers?
Dizziness, tiredness, blurred vision
Why are beta blockers used in heart failure?
They reduce the cardiac output which is advantageous because it reduces the work of the heart
Longer diastole which sloggers the heart rate allowing more oxygen to the heart
What happens when a patient already taking beta blockers need it for HF?
They have to switch to a heart failure specific beta blockers (Bisoprolol, carvedilol, nebivolol)
