Heart Failure Flashcards
Define the term “heart failure”
Clinical syndrome resulting in signs and symptoms because of an abnormality of the cardiac structure and/or function
Define the term “acute heart failure”
Acute heart failure refers to the sudden onset or worsening of the symptoms of heart failure
Acute heart failure may present with or without a background history of pre-existing heart failure.
What is the name given to acute heart failure without a bakcground of heart failure
de-novo acute heart failure
Acute heart failure may present with or without a background history of pre-existing heart failure.
What is the name given to acute heart failure with a background of heart failure
Decompensated acute heart failure
What are the two types of heart failure based on ejection fraction
Heart failure with reduced ejection fraction (HF-rEF)
Heart failure with preserved ejection fraction (HR-pEF)
Which type of heart failure typically has systolic dysfunction
a) Heart failure with reduced ejection fraction (HF-rEF)
b) Heart failure with preserved ejection fraction (HF-pEF)
a) Heart failure with reduced ejection fraction (HF-rEF)
Which type of heart failure typically has dystolic dysfunction
a) Heart failure with reduced ejection fraction (HF-rEF)
b) Heart failure with preserved ejection fraction (HF-pEF)
b) Heart failure with preserved ejection fraction (HF-pEF)
At what level is left ventricular ejection fraction refers to as reduced
< 35 %
What is the normal range of left ventricular ejection fraction
50-70%
Name a classification tool used in classifying heart failure based on the severity of symptoms
New York Heart Association Functional classification
What does “Left ventricular ejection fraction (LVEF)” refer to?
LVEF refers to how much blood is ejected from the left ventricle with each contraction
Left ventricular ejection fraction (LVEF) is measured by?
Measured using echocardiograph (ECHO)
What are the various grades of the New York Heart Association Functional classification
Graded from class 1 to 4, with class 1 being the least symptomatic and class 4 being the most symptomatic
Name some of the risk factors associated with heart failure
- Previous cardiovascular disease e.g., coronary heart disease
- Older age
- History of Diabetes
- Family history of ischaemic heart disease or cardiomyopathy
- Excessive alcohol intake or smoking
- Cardiac arrhythmias
- History of systemic conditions associated with heart failure e.g., sarcoidosis and haemochromatosis
- Previous chemotherapy
- Drugs that may exacerbate heart failure include NSAIDs, steroids, calcium channel blockers e.g., diltiazem and verapamil
Name some of the causes of heart failure with reduced ejection fraction (HF-rEF)
Ischaemic heart disease
Dilated cardiomyopathy
Myocarditis
Arrhythmias
Name some of the causes of heart failure with perserved ejection fraction (HF-pEF)
Hypertrophic obstructive cardiomyopathy
Restrictive cardiomyopathy
Cardiac tamponade
Constrictive pericarditis
Define Stroke volume
The amount of blood pumped out of the heart from each contraction.
Define Heart rate
The number of times the heart beats each minute
Define cardiac output
The amount of blood pumped out of the heart in one minute
What is the equation for cardiac output
CO = HR x SV
What is the equation for stroke volume
SV = End diastolic volume - End systolic volume
Define End-diastolic volume (EDV)
The amount of blood in the ventricles at the end of the loading phase/diastole, just before it is about to contract
Define end-systolic volume (ESV)
The amount of blood remaining in the ventricle at the end of systole
Define preload
Refers to how much the ventricular cardiomyocytes are stretched as a result of the pressure end-diastolic volume puts on them
Define afterload
Pressure or load against which the ventricles must contract
Define inotropy
Refers to myocardial contractility i.e. the force of muscular contractions
Define pulse pressure
Difference between systolic and diastolic blood pressure
Define mean arterial pressure
The average arterial pressure throughout one cardiac cycle.
What is the equation for mean arterial pressure
MAP = Diastolic BP + 1/3 Systolic BP
What happens in the heart during systole
When the ventricles depolarise/contract
What happens in the heart during diastole
The heart is repolarise/relaxation
Define Frank-Starling Law?
An increase end-diastolic volume causes an increase in preload. The increase in stetch of the cardiomyocytes of the left ventricle will increase the systolic force (stroke volume) causing an increase in cardiac output
↑ EDV ⇒ ↑ Preload ⇒ ↑ Stroke Volume ⇒ ↑ Cardiac Output
Describe the pathophysiology of heart failure
- As the heart fails the ventricular ejection fraction decreases i.e. the amount of blood that is ejected from the ventricles with each contraction
- This leads to an increase in end systolic volume (ESV) which in turn causes an increase in end-diastolic volume (EDV)
- A healthy heart would be able to compensate with this increase (as stated by Frank-Starling law)
- A failing heart however cannot compensate via the Frank-Starling law, as the heart is unable to increase its preload. Thus, there is a reduction in stroke volume and cardiac output.
What are some of the symptoms of heart failure
- Breathlessness – worsened by exertion
- Fatigue – reduced exercise tolerance
- Cough – frothy white/pink sputum
- Peripheral oedema
- Reduced exercise tolerance
- Orthopnoea – shortness of breathing when lying flat
Name some of the signs of heart failure
- Raised jugular venous pressure (JVP)
- Displaced apex beat
- Gallop rhythm (third heart sound)
What are the 4 components of the diagnostic workup of a patient with heart failure
- Clinical presentation
- B-type natriuretic peptide (BNP) blood test
- Echocardiogram (ECHO) – diagnostic test
- ECG
What is B-type natriuretic peptide (BNP)
B-type natriuretic peptide (BNP)
It is a protein which is released from the ventricles in response to myocardial stretch
B-type natriuretic peptide (BNP) is sensitive test but not specific for heart failure.
What does this mean?
Sensitive - if its negative it cannot be heart failure
Specific - if its positive, heart failure is a possibility however it is raised by other conditions as well
What is the normal level of B-type natriuretic peptide (BNP)
<400ng/mL
What is the raised level of B-type natriuretic peptide (BNP)
>400ng/mL
What is the name of the other natriuretic peptide that could be used in heart failure instead of B-type natriuretic peptide (BNP)
N-terminal pro-B-type natriuretic peptide (NT proBNP)
What other conditions cause a rise in B-type natriuretic peptide (BNP)
Diabetes, sepsis, old age, hypoxaemia such as PE and COPD, kidney disease and liver cirrhosis
What is the main investigation for the confirmation diagnosis of heart failure
Echocardiogram (ECHO)
What features of the ECHO are you checking in heart failure
Ventricular dysfunction is normally measured by the ejection fraction
<40% = heart failure with reduced ejection fraction (HF-rEF)
> 40% but raised BNP = Heart failure with preserved ejection fraction (HF-pEF)
Ventricular dysfunction <40% is diagnostic for what type of heart failure
Heart failure with reduced ejection fraction (HF-rEF)
Ventricular dysfunction >40% (with a positive BNP) is diagnostic for what type of heart failure
Heart failure with preserved ejection fraction (HF-pEF)
What ECG features may be present in heart failure
May reveal underlying causes of the heart failure e.g. ischaemic changes or arrhythmias
Name the 5 radiological features of heart failure on chest x-ray
- Alveolar oedema (indicated by “Cotton wool” appearance, perihilar consolidation, bat wing configuration)
- Kerley B lines (caused by interstitial oedema)
- Cardiomegaly (cardiothoracic ratio >0.5)
- Upper lobe venous diversion
- Pleural effusions (seen as blunting of the costophrenic angle, often bilaterally)
Bedside treat to investigate heart failure
- Observations
- Blood pressure
- Urinalysis – signs of renal failure
- Blood glucose – for underlying diabetes that may be contributing
Blood tests to investigate heart failure
- Full blood count (FBC) - exclude anaemia, infective cause.
- Urea and electrolytes (U&Es) - exclude renal failure as a cause of oedema.
- Thyroid function tests (TFTs) - exclude thyroid disease, a non-cardiac cause of HF
- Cholesterol- cardiovascular risk stratification.
- Liver function tests (LFTs) -exclude liver failure as a cause of oedema.
The management of heart failure is split into 3 categories
Lifestyle changes
Pharmaceutical intervention
Surgical options
What type of heart failure is lifestyle changes an important aspect of the management
Heart failure with reduced ejection fraction (HF-rEF)
AND
Heart failure with preserved ejection fraction (HR-pEF)
What type of heart failure is pharmaceutical intervention an important aspect of the management
Heart failure with reduced ejection fraction (HF-rEF)
Name some of the lifestyle modification that can aid in the management of heart failure
- Smoking cessation
- Salt and fluid restriction (improves mortality)
- Supervised cardiac rehabilitation
What is the 1st line pharmaceutical intervention for heart failure
ACE inhibitors and beta blockers
If patient is on ACEi and beta block but their symptoms of heart failure persistent what is the next line therapy?
ACEi + Beta blocker + Mineralocorticoid receptor antagonists (MRA)
Mineralocorticoid receptor antagonists (MRA) are contraindicated in what group of patients?
Contraindicated in hyperkalaemia, hyponatraemia, acute kidney injury
What type of diuretics can be useful in managing a patient’s heart failure symptoms (but does not impact their mortality)
Loop diuretics such as furosemide or bumetanide
Describe the mechanism of action of loop diuretics
Loop diuretics inhibit the sodium-potassium-chloride cotransporter in the thick ascending limb
This transporter normally reabsorbs a lot of sodium so inhibition causes a rise in distal tubular concentration of sodium, water stays with the sodium
This leads to increased water and sodium loss.
Name some of the side effects of loop diuretics
Dehydration and reduced serum sodium and potassium
Give an example of a loop diuretic
Furosemide
Give an example of an Angiotensin-converting enzyme (ACE) inhibitors
Ramipril
Describe the mechanism of action of Angiotensin-converting enzyme (ACE) inhibitors
ACEi inhibits the conversion of Angiotensin I to Angiotensin II
Angiotensin II can no longer stimulate the release of aldosterone from the adrenal glands
Aldosterone is important for sodium reabsorption (which is followed by water) and potassium and hydrogen secretion
This this decreases blood volume.
Name some of the side effects of an Angiotensin-converting enzyme (ACE) inhibitors
Dry cough
Hypotension
Renal impairment thus renal function must be checked prior to initiation and repeat tests within 1-2 weeks
Give an example of an Angiotensin receptor blockers (ARBs)
Losartan
What is the mechanism of action of Angiotensin receptor blockers (ARBs)
ARBs inhibit the binding of angiotensin II to angiotensin I by competitive binding to the angiotensin I receptors.
Give an example of a beta blocker
Bisoprolol
What is the mechanism of action of beta blockers
Act to reduce sympathetic activity, an important compensatory mechanism that causes vasoconstriction increasing the systemic resistance i.e. afterload and thus it reduces the strain of the myocardium
beta-1 receptors are found predominantly where?
In the heart
beta-2 receptors are found predominantly where?
Found in the lungs
Give an example of a Mineralocorticoid receptor antagonists (MRA)
Spironolactone
What is the mechanism of action of Mineralocorticoid receptor antagonists (MRA)
MRA binds to the mineralocorticoid receptor causing the inhibition of aldosterone. Aldosterone is important for sodium reabsorption (which is followed by water) and potassium and hydrogen secretion.
This decreases blood volume, putting less strain on the myocardium
