Cardiac Failure 2: Clinical Management Flashcards
What should all patients with LVSD receive?
Angiotensin-converting enzyme inhibitor
Beta blocker
What should all ps with oedema receive?
Diuretic
Example of ACEI
Ramipril
Action of ACEIs
Inhibits ACE which converts angiotensin I to angiotensin II in RAA system
Effect of ACEIs
Reduce arterial and venous vasoconstriction (reduce after- and pre-load)
Reduce salt/water retention, hence reduce circulating volume
How to use ACEIs and when?
Low dose
Monitor urea/creative and K+ before and during treatment
Hypertension
Inhibit RAA system to prevent cardiac remodelling, improves function of myocyte
Side effects of ACEIs
Severe hypotension
Deterioration of renal function in pre-existing renal disease
10% have dry cough
When should ACEIs not be used?
And why?
Renovascular disease
Substantial drop in BP, kidney under perfused, damage to kidney
What happens in kidney when renal blood flow is impaired?
Renin produced to maintain blood pressure
What is bilateral renal artery stenosis ?
Plaque in both arteries of kidneys
Action of AT1 receptor antagonists
Block action of angiotensin II by blocking AT I receptors
Therefore no vasoconstriction and no aldosterone produced
Example of AT1 receptor antagonists
Iosartan
Why might AT 1 receptor antagonists be used instead of ACEIs?
Less likely to give cough
Example of beta blocker
Effect
Bisoprolol
Beta 1 selective
Reduce disease progression, symptoms and mortality
Use of beta blockers
Use in stable, moderate failure
care needed for COPD
Failure related with ischaemia - useful
Start with low dose
Effect of beta blocker
Reduce sympathetic stimulation, heart rate and O2 consumption
Antiarrhythmic: will control rate in atrial fibrillation
Oppose the neurohormonal activation which leads to myocyte dysfunction
Symptoms may get worse at first
Most common diuretics and effect
Loop diuretics eg. Furosemide
Very powerful
Reduce circulatory volume and oedema
What can loop diuretics cause
Hypokalaemia - reduction of K+ on the blood
Especially thiazides
What do spironolactones do
Aldosterone receptor antagonists
Reverse LV hypertrophy
Action of digoxin
Positive inotrope by inhibiting Na+/K+ ATPase
Na+ accumulates in myocyte, pushed out, exchanged with Ca2+ - compensation
Leads to increased contractility
Why does Ca2+ build up due to digoxin?
Na/Ca exchange compensation
In repolarisation, Na gradient is reduced which reduces efflux of Ca
What does digoxin do in AF?
Slows heart rate, improving cardiac filling
Impairs AV conduction and increases vagal activity
Other specialist drugs
Ivebradine
Sacubitril valsartan
Ivabradine effect
Inhibits funny current
Used with ACEI/beta blocker and MRA
Sacubitril valsartan effect
Neorikysin inhibitor
Endopeotidase inhibitor
What is prescribed with main heart failure drugs?
Vasodilator - nitrates, prazosin, hydralazine
Positive inotropes - final approach, phosphodiesterase inhibitors, amines
What to monitor?
Renal function
Use of ACEi – care in mild-moderate failure, contraindicated in renovascular disease
Potassium
Hypokalaemia a major problem [aldosterone]
Side effect of thiazides/loop diuretics
Enhances effects of digoxin
When is there a serious possibility of hyperkalaemia?
NB serious possibility of hyperkalaemia with ACEi if used with a K+ sparing diuretic
Why is monitoring renal function important ?
Elderly - GFR may be impaired
Important for drug handling, dose of digoxin
Why is digoxin monitored?
Digoxin toxicity Major problem Narrow therapeutic window Digoxin – anorexia, nausea (suggest dose too high), visual disturbances, diarrhoea Digoxin in AF, monitor pulse (>60bpm)
When is an ATRA used?
When LV dysfunction p has a cough
