Therapeutics of Heart failure Flashcards
what are the 3 types of heart failure
- heart failure with reduced ejection fraction (HFrEF)
- heart failure with mildly reduced ejection fraction (HFmrEF)
- heart failure with preserved ejection fraction (HFpEF)
what is the diagnostic criteria for HFrEF
- symptoms and signs
- LVEF <40%
what is the diagnostic criteria of HFmrEF
- symptoms and signs
- LVEF 41-49%
what is the diagnostic criteria for HFpEF
- symptoms and signs
- LVEF>50%
- objective evidence of cardiac structural/functional abnormalities consistent with the presence of LV diastolic dysfunction/raised LV filling pressures, including raised natriuretic peptides
is heart failure a progressive condition
often a persistent and progressive conditionm
what are the aims of therapy for treating heart failure
1, improve life expectancy
2. improve quality of life
how can we achieve these aims of therapy
- early and accurate diagnosis
- prescribe in line with the evidence base- drugs, monitoring, exercise and devices
- encourage self management
- good access to professional health
- reduce admissions, readmissions and length of stay - good end of life care
what is involved in the history and examination of heart failure
- detailed history- current symptoms and PMH
- patient examination
- signs and symptoms
- ECG
- chest x ray - blood tests- renal function, FBC, thyroid, HbA1c, LFT
- natriuretic peptides
- NT- pro BNP - echocardiogram- dimensions/function of heart
- valves, systolic and diastolic function
what investigations can be conducted to evaluate possible aggravating factors or alternative diagnosis
- ECG
- Chest X ray
- urinalysis
- peak flow or spirometry
- blood tests
what does NT pro BNP stand for
n-terminal pro B type natriuretic peptide
what do natriuretic peptides do
- they promote natriuresis
- inhibit ADH and aldosterone release
- cause arterial and vasodilation
- synthesised in myocardial cells in response to raised ventricular pressure
- levels can be raised in heart failure
what do high levels of Natriuretic peptides suggest
suggests heart failure
- levels don’t differentiate between HFrEF or HFpEF
- can also be raised for other reasons (AF, renal impairment)
what can reduce natriuretic peptide levels
- obesity
- afro caribbean patients
- patients already on treatment with diuretics, ACE inhibitors, beta blockers, ARBs and aldosterone antagonists
why is an echocardiogram performed
- transthoracic doppler 2d echocardiogram
- performed to exclude important valve disease, assess systolic and diastolic function of heart
what are the heart failure classifications in terms of physical activity
- class I- no limitation of physical activity, ordinary physical activity doesn’t cause symptoms
- class II- slight limitation of physical activity, comfortable at rest, ordinary physical activity causes symptoms
- class III- marked limitation of physical activity, comfortable at rest, but less than ordinary activity causes symptoms
- class IV- Severe limitation and discomfort with any physical activity, symptoms persist even at rest
what is the 1st step in pharmacological intervention in heart failure
offer diuretics to control symptoms
- reduce fluid retention and minimise congestive symptoms
what needs to be carefully monitored in use of diuretics
- renal function
- weight
- electrolytes
what are the different types of diuretics used for heart failure
- loop diuretics- furosemide, bumetanide
- thiazide diuretics- bendroflumethiazide
- combination of loop and thiazide diuretics
- mineralocorticoid receptor antagonists- spironolactone, epleronone
describe the absorption of loop diuretics and how they are given
- furosemide has inter and intra patient variability of absorption
- in hospital, given as IV: bolus or continuous infusion
- step down to oral: 48 hour rule - bumetanide better absorbed in fed state
- 40mg of furosemide= bumetanide 1mg - monitor electrolytes
describe how thiazides are used in heart failure
- only used alone in mild HF (usually for hypertension)
- ineffective in poor renal function
- monitor potassium, sodium, magnesium and calcium
- may exacerbate diabetes and gout
- metolazone alone is a weak diuretic but very potent when combined with loop diuretic
what does raised aldosterone lead to
leads to sodium and water retention
- peripheral oedema and congestion
- vasoconstriction, causing hypertension
- hypokalaemia and hypomagnesia which may induce electrical instability and death of cardiac myocytes
- myocardial hypertrophy and fibrosis
. blocking of aldosterone shown to be beneficial in HFrEF
what can be added to reduce fluid retention and abdominal oedema
can add mineralocorticoid receptor antagonists
how are ACE inhibitors used in heart failure
- prevent myocardial hypertrophy and remodelling
- relieve symptoms and hospitalisations
- improve exercise tolerance
- reduce acute exacerbations
- reduce mortality
- improve survival and prevent progression of symptoms
- used in all patients with HFrEF, EF<40% regardless of symptoms
outline examples of ACE inhibitor survival trials
- SAVE trial- first ACE inhibitor post MI study
- pts EF<40% post MI
- captopril vs placebo
- captopril reduced mortality BY 25%
- results replicated in other studies - ATLAS trial- more benefit with higher doses