12.4 Clinical management of Heart Failure Flashcards
What is required for a normal cardiac function?
- Myocardial contractility
- Effective blood supply
- Effective conduction system
- Effective valve function
What is heart failure often due to?
Due to:
- Cardiovascular disease
- Cardiac stressors/events
What is heart failure?
- Heart failure is a complex syndrome in which the ability of the heart to maintain the circulation of blood is impaired as a result of a structural or functional impairment of ventricular filling or ejection, resulting in a reduced cardiac output and/or elevated intracardiac pressures at rest or during stress
- Characterised by typical symptoms
- e.g. breathlessness and fatigue
- May be accompanied by signs
- e.g. elevated jugular venous pressure, pulmonary crackles and peripheral oedema
Explain the pathophysiology of heart failure
-
Decreases in cardiac output detected by baroreceptors in the aortic arch lead to:
- Reduced blood flow to the kidneys, reducing glomerular filtration and the accumulation of salt and water increasing preload.
- Activation of the RAAS, further exacerbating fluid and water retention to maintain BP and stimulation of the sympathetic nervous system forcing the heart to work harder by increasing heart rate and constricting the blood vessels increasing afterload. Becomes a vicious cycle
- Initially these are compensatory mechanism to maintain adequate output but over time becomes unsustainable and the heart begins to struggle (end up with ascites, congested liver and peripheral oedema)
- If the left side of the heart is not functioning correctly the pressure build up ends up being in the lungs causing lung congestion and pleural effusions.
What is the definition of prevalence?
Total number of cases (e. in the UK)
What is the definition of incidence?
Is the number of new cases (e.g. per year in the UK)
What are the risk factors of heart failure?
- Age (older)
- Gender (male)
What are the causes of heart failure?
- Ischaemic heart disease (MOST COMMON) (angina, MI)
- Lung disease
- Arrhythmias (can be reversed)
- Cardiotoxins eg. Chemotherapy, alcohol, illicit drugs (can be reversed)
- Congenital heart disease
- Genetic cardiomyopathies e.g. dilated or hypertrophic cardiomyopathy
- Hypertensive heart disease
- Infection eg. Myocarditis, Infective endocarditis
- Pregnancy
- Thyroid disease / Anaemia (can be reversed)
- Valvular heart disease
Explain ischaemic heart disease (to do with heart failure)
- Leads to damage/death of cardiac tissue, regional movement abnormalities of muscle and reduced contractility
Explain valve disease (to do with heart failure)
- Valves can either become stenotic – stiff and struggle to open
- Restricting blood flow through them
- Regurgative – leaky and don’t close properly – blood flows back through them when they close
Both affecting the functioning and output if the heart which can lead to heart failure
Explain cardiomyopathies (to do with heart failure) & the different types
Cardiomyopathy is a disease of the heart muscle that makes it harder for your heart to pump blood to the rest of your body & can lead to heart failure
Hypertrophic
- Muscle of the ventricles become thickened reducing the volume the ventricle can hold and the amount it can then force out during systole (often don’t get a change in EF)
EF (ejection fraction)– ratio of the amount of blood that can be forced on in a single contraction as a proportion of the volume if can hold. (amount of blood pumped out / amount of blood in the chamber) In this case smaller volume and smaller output but normal EF
Restrictive
- Muscle walls become more fibrous and don’t move in the same way, altered filling and ejection – variable EF depending on ration
Dilated
- Muscle walls are thin and stretched holding a larger volume but without the muscle capacity to force the blood out during diastole and hence a reduced EF
What are the different ranges of ejection fraction?
- 55-70% = PRESERVED EF
- 41-49% = MID-RANGE EF
- LESS than (or same) as 40% = REDUCED EF
What investigations if you suspected heart failure?
In history: breathlessness (worse at night when lying down, need to sit up), peripheral oedema
Family history & medication history
Investigations
- CXR
- ECG
- FBC
- U&Es
- LFTs
- TFTs
- BNP
What is BNP & what is its link to heart failure?
- Is a hormone secreted by cardiomyocytes in the ventricles in response to stretching
- Elevated in blood tests = HF
If elevated could also mean (increase AGE, arrhythmias, surgery):
- Acute renal failure and chronic renal failure
- Hypertension (HTN)
- Pulmonary diseases such as: pulmonary hypertension, severe chronic obstructive pulmonary disease (COPD), pneumonia, pulmonary embolism
What are the different types of heart failure?
- HFrEF - reduced
- HFpEF – preserved
- HFmrEF – mid range
- Systolic dysfunction
- Diastolic dysfunction
- Left
- Right
- Cor pulmonale
- Low output (e.g. tachy/bradycardia arrhythmias due to LV)
- High output (e.g. INCREASE demand for oxygen - pregnancy, anaemia, hyperthyroidism)
- Valvular
- Arrhythmic
Explain the disease trajectory in heart failure patients
- Difficult to predict
- Frequent admissions
- Poor quality life
- Depression / anxiety
- Palliative care
