Heart Failure Flashcards
Define heart failure.
Severe failure of the heart to function properly, so the heart is unable to pump enough blood to meet the body’s demmands.
How is heart failure defined based on LVEF?
Heart failure with reduced ejection fraction (HFrEF)
Heart failure with mid-range ejection fraction
(HFmrEF) Heart failure with preserved ejection fraction (HFpEF)
Heart failure with reduced ejection fraction (HFrEF)
LVEF <40%
Heart failure with mid-range ejection fraction (HFmrEF)
LVEF 40-49%
Heart failure with preserved ejection fraction (HFpEF)
LVEF >50%
What is the most common form of heart failure?
HFrEF due to impaired contraction of the left ventricle.
What is heart failure caused by?
Heart failure is caused by a structural and or functional cardiac abnormality that results in reduced cardiac output or elevated intracardiac pressures at rest or during stress.
In patients with HFrEF what does myocardial injury result in?
Myocardial injury results in maladaptive changes in myocytes and extracellular matrix which leads to pathological ventricle remodelling with ventricular dilation, and impaired ventricular contraction.
Cycle of HF with reduced ejection fraction:
Right heart failure progression
What does sustained RAAS system activation in heart failure lead to?
What does sustained activation of the SNS in HF lead to?
Explain the role of natriuretic peptides in cardioprotection.
What are natriuretic peptides released in response to?
The stretching of heart muscles.
How do natriuretic peptides function as important biomarkers in heart failure?
As heart failure progresses, activation of the SNS and RAAS system leads to increased blood volume and sustained myocardial stretch, resulting in elevated levels of circulating BNP.
Natriuretic peptides oppose the actions of RAAS, how is this affected in heart failure?
In heart failure, peripheral resistance to NP’s occurs, which results in RAAS signalling being unopposed.
- Reduced NP action in heart failure contributes to the volume overload and vasoconstriction.
Progression of HFrEF can be attributed to two main mechanisms:
- Additional myocyte death due to occurence of events such as recurrent myocardial infarction.
- Decline in systolic functioning triggers a response in neurohormonal signalling pathways, which initiates systemic responses that cause additional strain on the heart.
Neurohormonal signalling pathways activated in HFrEF:
New York Heart Association Classification of Heart Failure:
Diabetes and hypertension are two conditions that increase the risk of developing and worsen the prognosis of heart failure.
- renal dysfunction is also closely linked.
Diabetes and hypertension are two conditions that increase the risk of developing and worsen the prognosis of heart failure.
- renal dysfunction is also closely linked.
What are the clinical presentations of heart failure?
- Assessment of baseline NYHA
- BP/Sats/HR
- Orthopnoea/pillows/sleeping/appetite
- Chest examination/JVP
- Heart sounds/added sounds/murmurs
- Abdo/ascites/hepatic distension
- Peripheral/odema/rash/muscle bulk-cardiac cachexia
What is meant by cardiorenal syndrome?
Cardiorenal syndrome (CRS) is an umbrella term used in the medical field that defines disorders of the heart and kidneys whereby “acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other”.
What routine lab tests are done to investigate
FBC +/- iron studies - ensure patient is not anaemic.
U+E+creatinine or GFR to test kidney function.
HBA1c - blood sugar.
Albumin and clotting - to chest liver function.
BNP - biomarkers.
Cholesterol and lipids.
Functions of BNP
Vasodilation, natriuresis, diuresis.
What is the normal LVEF?
A normal left ventricular ejection fraction (LVEF) ranges from 55% to 70%.
What investigations are done in suspected heart failure?
Transthoracic Echocardiography
ECG
Radionuclide angiography - for LVEF
CMR
NT-proBNP
Non-metabolically active precursor of BNP.
How does adenosine affect the heart?
Adenosine is a coronary artery vasodilator.
What is cardiovascular magnetic resonance used for in heart failure?
CMR shows cardiac function, structure (tissue characterization), perfusion, and viability.
What are the functions of cardiac troponins?
Regulatory proteins that control interactions between actin and myosin - released in the break down of cardiac muscle in infarction.
What are transthoracic echocardiograms used for in heart failure?
Used to image the internal structures of the heart.
Transthoracic echocardiograms are used to show signs of heart disease, such as weak heart muscle, blood clots inside the heart, or poorly functioning heart valves.
Angiotensin II binds to what receptors?
AT1 and AT2 receptors.
Where are AT1 receptors located and what do they mediate when they bind angiotensin II?
The AT1 subtype is found in the heart, blood vessels, kidney, adrenal cortex, lung and brain and mediates the vasoconstrictor effects.
What is the first line treatment for heart failure?
ACE inhibitors.
Angiotensin receptor blockers
What other treatments are considered in heart failure?
ACE inhibitors
Aldosterone antagonists
Beta blockers
What are the major diagnostic criteria in HF?
Reduced LVEF.
BNP >100pg/ml
Iron deficiency - serum ferritin <100ng/ml
Hb less than 15g/dL
Natriuretic peptides, adrenomedullin, bradykinin, substance P, calcitonin gene related peptide are all examples of what?
Endogenous vasoactive peptides
- Decrease neurohormonal activation, decrease vascular tone, decrease cardiac fibrosis hypertrophy, decrease sodium retention.
What are the non-pharmacological treatments for heart failure?
Fluid intake / diet
Cardiac / HF rehabilitation
Psychological support
CPAP - sleep apnoea associated with HF.
Pathophysiology of iron deficiency in HF:
What are the two types of heart failure?
The heart’s ventricles can’t pump blood hard enough during systole, called systolic heart failure.
Not enough blood fills into the ventricles during diastole, called diastolic heart failure.
Ejection fraction =
Ejection fraction = stroke volume / total volume
In what type of heart failure is there a reduced pre-load?
Diastolic heart failure - not enough blood has filled the heart before contraction.
Frank starling mechanism
The Frank–Starling law of the heart represents the relationship between stroke volume and end diastolic volume. The law states that the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles, before contraction, when all other factors remain constant.
What is left sided heart failure usually caused by?
Usually due to systolic failure which results from damage to the myocardium which means it can’t contract as forcefully.
What is the main cause of damage to the myocardium of the heart?
Ischemia due to atherosclerosis.
How does hypertension lead to heart failure?
This is because as arterial pressure increases in the systemic circulation, it gets harder for the left ventricle to pump blood out into that hypertensive systemic circulation.
How does the left ventricle respond to hypertension?
To compensate, the left ventricle actually bulks up, and its muscles hypertrophy, or grow so that the ventricle can contract with more force.
The increase in muscle mass also means that there is a greater demand for oxygen, and, to make things even worse, the coronaries get squeezed down by the this extra muscle so that even less blood’s delivered to the tissue.
- propagates heart failure.
What is dilated cardiomyopathy?
Dilated cardiomyopathy, is where the heart chamber dilates, or grows in size in an attempt to fill up the ventricle with larger and larger volumes of blood, or preload, and stretch out the muscle walls and increase contraction strength, via the Frank-Starling mechanism.
- eventually ventricle wall becomes thinner leading to systolic heart failure.
How does hypertension cause diastolic heart failure?
Hypertension leads to hypertrophy of the ventricles - this decreases the volume of space available = decrease pre-load leading to diastolic failure.
What conditions can cause concentric ventricular hypertrophy?
Aortic stenosis
Hypertrophic cardiac myopathy
Hypertension
What can persistent activation of the RAAS system lead to?
Fluid retention which can cause peripheral and pulmonary oedema.
What causes pulmonary oedema and how does this present in heart failure?
Increased fluid retention, increased pressure in the pulmonary heart and veins leading to pulmonary oedema.
Presents with dyspnea and orthopnea.
In cases of pulmonary oedema what is heard on ausculation?
Crackles indicating fluid in the lungs.
What are common causes of right sided heart failure?
Left sided heart failure
Atrial / ventricular septal defect allowing left to right shunt.
What clinical sign is highly suggestive of right sided heart failure?
Elevated JVP
Where does peripheral oedema most commonly affect and why?
The legs due to gravity.
Why are pacemakes given to some people with heart failure?
It is common for people with heart failures to develop arrhythmia’s.
Natriuresis
Excretion of sodium in the urine.
Where is BNP produced?
Ventricular myocytes in response to ventricles stretching due to increased ventricular volume.
What are the actions of BNP?
Vasodilation
Natriuresis
Diuresis
BNP is produced in response to what?
Fluid overload
Systolic murmur indicates what valve abnormalities?
Aortic stenosis
Mitral regurgitation
What are classed under the umbrella term of ACS?
Unstable angina
NSTEMI
STEMI
How does heart failure lead to death?
Sudden death due to arrythmia’s - hence why people have defibrilators put in.
General deteroration in heart function.
What is the treatment for heart failure?
(acute decompensated)
Oh - Oxygen
My - Morphine
Fucking - Furosemide
God - GTN
Sit up - sit up
Note: CPAP, Adrenaline, short term stop beta blockers
What is used in the long term management of heart failure?
- Ace inhibitor
- Beta blocker
- Aldosterone antagonist
- Diuretics
- Specialist management
