Heart Failure

Question 1

Ultimately, what is inadequate in heart failure

Answer 1

Cardiac Output

Question 2

Describe the normal circulation

Answer 2

The body has two circulations (pulmonary and systemic)

Each pump is linked to the vessels in front and behind – thus what affects one side will eventually affect the other

Question 3

Define Cardiac output

Answer 3

The volume of blood leaving EITHER side of the heart per minute (usually in context of left ventricle)

Question 4

What does stroke volume depend on

Answer 4

Contractility
Preload
Afterload

Question 5

What happens to contractility in heart failure

Answer 5

Inadequate contractility can compromise SV

Question 6

What happens to preload in HF

Answer 6

Inadequate venous return can compromise SV

Question 7

What happens to afterload in HF

Answer 7

Excessive resistance compromises ejection volume

Question 8

Explain the consequences of impaired contractility

Answer 8

EF reduced.
Starling curve shifts downwards
SV reduced for any end-diastolic BP (preload)

Question 9

Describe the thresholds for EF

Answer 9

≥55%
Normal
45-54%
Mildly reduced
30-44%
Moderately reduced

<30%
Severely reduced

Question 10

How do we measure EF

Answer 10

Transthoracic echocardiogram (chest ultrasound).

Question 11

Define heart failure

Answer 11

“A clinical syndrome caused by the inability of the heart to supply blood to the tissues
sufficient to meet their metabolic needs, or achieved at the expense of elevated filling pressures.”

Question 12

Outline what is meant by heart failure

Answer 12

Inability of the heart to keep up with demand
Inadequate perfusion of organs (e.g. brain, liver, kidneys)
Congestion in lungs and legs
Collection of signs and symptoms

Question 13

What often happens in heart failure

Answer 13

Heart rate increases to maintain Cardiac Output.

Question 14

Describe dilated cardiomyopathy

Answer 14

Walls of ventricles are thinner- so less pressure generated- Law of Laplace.

Question 15

Describe left heart failure

Answer 15

Dysfunction associated with the left ventricle
Ejection or filling issue
Blood backs up into the lungs causing congestion
Breathlessness, couging , wheezing
‘Respiratory symptoms’

Also dizziness and cyanosis

Question 16

Explain the respiratory symptoms observed in left hear failure

Answer 16

Increased congestion into the pulmonary circulation, and can cause further backpressure and congestion into the systemic venous circulation.
Increases hydrostatic pressure in the lungs- leading to pulmonary hypertension and oedema- leading to SOB an other respiratory symptoms.

Question 17

Describe right heart failure

Answer 17

Dysfunction associated with the right ventricle
Ejection or filling issue
Increased afterload of the pulmonary circulation (pulmonary hypertension)
Often secondary to left heart failure

Question 18

What are the consequences of Right Heart Failure

Answer 18

Not enough oxygen supplied- ischaemia- cell death.

Causes congestion of the systemic veins.

Question 19

Describe acute heart failure

Answer 19

Rapid onset

Symptoms similar to chronic HF, except the timing of onset and worsening is much more severe

Question 20

Describe chronic heart failure

Answer 20

Slow onset

Due to Infection, pulmonary embolism, myocardial infarction or surgery

Question 21

Describe HF with reduced EF (HFrEF)

Answer 21

Abnormal systolic function
Impaired contraction of the ventricles which despite an increase in HR results in decreased cardiac output
Typically, weakness is caused by damage or destruction of the ventricular myocytes (or valve abnormalities [decreased SV with normal/increased EDV])
Weaker ejection leads to higher diastolic pressures
Can’t expel blood

Question 22

Describe HF with preserved EF (HFpEF)

Answer 22

Abnormal diastolic function
Normal contraction of the ventricle
Increased stiffness of ventricle, impaired relaxation or impaired filling
Because EDV is inherently reduced, the reduced stroke volume is masked when looking at ejection fraction
Can’t gain blood

Question 23

What may cause HFpEF

Answer 23

Restrictive cardiomyopathy- ventricles are stiffer- they cannot relax- majority of cases of HF
Hypertrophic cardiomyopathy- hypertrophy of the ventricular myocardium, particularly the interventricular septum- hypertrophy inwards- smaller space for blood to fill the ventricle.

Question 24

What are the consequences of HFpEF

Answer 24

Less space for blood to pool in diastole- reduced CO

Question 25

Describe valve disease as a cause of heart failure

Answer 25

mitral/tricuspid problems mean ventricles cannot fill with blood, pulmonary/aortic valve means cannot expel blood (systolic issue)

Question 26

Describe Ischaemic Heart Disease as a cause of heart failure

Answer 26

Narrowing of coronary arteries cause ischaemia in heart muscle Most common cause of HF Cell death Less cells to perform role- but no oxygen supplied to be able to perform more work to compensate.

Question 27

Describe MI as a cause of heart failure

Answer 27

Significant occlusion leads to death of heart muscle

Question 28

Describe hypertension as a cause of heart failure

Answer 28

Hypertension increases afterload which means ventricle must work harder Compensatory left ventricle hypertrophy occurs- this impairs diastolic filling- increasing myocardial oxygen demand (need more oxygen which not supplied so die), so muscle grows inward (reducing space for filling)

Question 29

Describe dilated cardiomyopathy as a cause of heart failure

Answer 29

Dilated LV reduces generatable pressures which reduces ejection

Question 30

Describe hypertrophic cardiomyopathy as a cause of heart failure

Answer 30

Increased LV thickness reduces internal ventricular volume & impedes filling

Question 31

List the most common causes of HF in order

Answer 31

1. CAD 2. Hypertension and cardiomyopathy 3. Valve disease 4. Myocarditis and neoplasia 5. other

Question 32

What is the most common cause of RHF

Answer 32

LHF

Question 33

Describe the causes of RHF

Answer 33

Right ventricular MI Cor pulmonale: RHF due to disease of the pulmonary vasculature. It can be caused by recurrent pulmonary emboli, primary pulmonary hypertension or any widespread hypoxic pulmonary vasoconstriction such as COPD. All of these increase pulmonary vascular resistance causing pressure and volume overload of the right ventricle. Decreased right ventricular CO limits LV preload and thus LV SV

Question 34

Describe the features of HF seen in the patient

Answer 34

orthopnoea- shortness of breath in supine position. When supine, blood redistributes to the intrathoracic compartment increasing pressures and alveolar oedema. It can be relieved by sitting upright, and patients will report that they have to sleep with multiple pillows. Exertional breathlessness Weight loss Anorexia Paroxysmal nocturnal dyspnoea- patients wake up in the night gasping for breath- alveolar oedema caused by pulmonary venous congestion Fatigue Nocturia- peripheral oedema is reabsorbed in the circulation when supine- circulating volume increases and is compensated by an increase in urinary output.

Question 35

Describe the clinical features of HF

Answer 35

ascites, hepatomegaly ( due to hepatic venous congestion), increased JVP, reduced pulse volume, tachycardia Pitting oedema- due to oedema from increased fluid filtration caused by increased venous pressure.

Question 36

Describe some of the investigations that we may use for HF.

Answer 36

Chest X-Ray- May show an enlarged heart shadow due to dilatation and alveolar shadowing due to oedema. There may be small bilateral pleural effusions. Width of heart shadow greater than half the transthoracic diameter. Echocardiogram- Key investigation- allows quantification of EF- indicating the degree of systolic dysfunction. Allows assessment of ventricular dilatation and valvular disease BNP- B natriuretic peptide- released in response to vascular stretch and is a very sensitive marker for heart failure Exercise Test Ambulatory ECG- atrial fibrillation, ventricular hypertrophy or left bundle branch block- if ischaemic- ST elevation indicates previous MI. Angiogram

Question 37

Describe raised jugular venous pressure

Answer 37

Direct measure of pressure in right atria (increases with increase in RJVP)- shows degree of HF Increased pressure in right side of heart leads to pressures backing up into systemic veins, especially visible in jugular vein.

Question 38

Describe pitting oedema

Answer 38

Fluid accumulation in tissue (especially of lower extremities) leads to a pitting effect when physically depressed. The indentation is visible for a short period

Question 39

Describe Ascites

Answer 39

Fluid accumulation in peritoneal cavity

Question 40

What is meant by natriuresis

Answer 40

Sodium excretion

Question 41

What are the effects of BNP and when is it released

Answer 41

Released from ventricular myocytes in response to stretch Vasodilation of microvessels- reducing BP, afterload- less strain on ventricles Reduced aldosterone secretion- LESS NA+ absorption Reduced sodium reabsorption Inhibits renin secretion Reduced ECF- reducing circulatory volume and thus pressure Reduced pressures

Question 42

Describe the use of BNP in HF

Answer 42

Good marker of HF | BNP > 100 pg/mL (<70y) or >300 (>70y) suggestive of heart failure

Question 43

Describe the conservative treatment of HF

Answer 43

Weight loss Smoking cessation Less alcohol Regular exercise

Question 44

What are the aims of treatment for HF

Answer 44

Decrease preload Decrease afterload by reducing both ventricular volume and pressure Limit heart rate Reverse or limit ventricular remodelling.

Question 45

Which treatments should we start with

Answer 45

ACE inhibitors and beta blockers. | Also diuretics- to get rid off excess fluid.

Question 46

Describe ACE inhibitors

Answer 46

Limits ventricular remodelling Reduces afterload of the heart (by removing its vasoconstrictor effect) Limits salt and water retention.

Question 47

Describe beta blockers

Answer 47

Beta blocker bisoprolol or carvedilol; NOT atenolol or metoprolol Reduce heart rate, increase coronary blood flow The decreased contractility and heart rate, however, may worsen symptoms and thus they should only be given in low doses

Question 48

What should be given next if EF is still low

Answer 48

As EF<35% if still symptomatic spironolactone or eplerenone

Question 49

Which treatments should then be considered if the patient is still symptomatic

Answer 49

ivabradine (if HR>70) to cause vasodilation and sacubitril (inhibits enzyme to break down BNP)/valsartan (stops aldosterone being produced)- if ACE I tolerated.

Question 50

When should you consider Cardiac Resynchronisation therapy

Answer 50

if LBBB/RBBB, then this can allow more efficient contraction Consider CRT if QRS >130ms and LBBB or QRS >150 and RBBB

Question 51

What are the NICE guidelines for the treatment of HF

Answer 51

New HF diagnosis Start ACE inhibitor and titrate upwards (Angiotensin receptor blocker if ACE-intolerant) Add beta blocker and titrate upwards (Assuming no contraindications and patient is stable) Add spironolactone (diuretic) (if patient remains moderately to severely symptomatic)

Question 52

What must also be given alongside these treatments

Answer 52

Add diuretic In most cases Add digoxin If normal rhythm and symptomatic despite ACE inhibitor and beta blocker If AF present

Question 53

Describe the non-pharmacological treatment for fluid control

Answer 53

Haemoflitration Peritoneal dialysis Haemodialysis

Question 54

Describe the devices available for patients with HF

Answer 54

Intra-aortic ballooning CRT Ventricular Assist Device (VAD)/Total artificial heart.

Question 55

Describe the surgical treatments of HF

Answer 55

Coronary artery bypass graft Valve surgery Transplant- severe, intractable HF- life-long immunosuppression.

Question 56

Describe the VAD

Answer 56

Implantation of mechanical ventricular assist devices which take over the work of the failing ventricles- used as a temporary solution until transplantation.

Question 57

Describe the Law of LaPlace

Answer 57

Wall stress= PR/2 x wall thickness =PV/LV mass Increased wall thickness reduced wall stress but less space for the blood to pool.

Question 58

Describe compensatory hypertrophy

Answer 58

reduces wall stress in response to acute load, but then leads to dilated cardiomyopathy as ventricle volume has reduced - increasing wall stress; thin wall can no longer contract with enough force to eject blood

Question 59

Describe the beneficial physiological response to heart failure

Answer 59

BNP released when ventricular myocytes stretched; vasodilation, reduced aldosterone and reduced BP

Question 60

Describe the pathological response to heart failure

Answer 60

Reduced renal perfusion leads to activation of RAAS, leading to aldosterone production and hence vasoconstriction, sodium/water retention, and blood pressure increases This is initially in place to increase filling pressures and to maximise stroke volume, but soon filling pressures become excessive and stroke volume decreases due to over-stretching of the myocytes- moves them onto the downward part of the starling curve.

Question 61

What are the consequences of compensatory tachycardia

Answer 61

Reduces the duration of diastole, and thus the duration of coronary flow. With the increase in contractility, myocardial oxygen demand is increased while oxygen delivery is reduced. These two factors combined may cause myocardial ischaemia, which will further impair function.

Question 62

What is it like to live with HF

Answer 62

Patient is breathless and tired, sometimes at rest Heart is damaged and a less effective pump Marked neurohormonal activation Poor QoL Life expectancy is reduced

Question 63

What is the functional NHYA classification

Answer 63

Based on a patients physical limitations Class 1- No limit of physical activity. Ordinary physical activity does not cause fatigue, palpitations or dyspnoea Class 2- Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, palpitations and dyspnoea Class 3- Marked limitation of physical activity. Comfortable at rest but less than ordinary physical activity results in fatigue, palpitations and dyspnoea Class 4- Unable to carry out any physical activity without discomfort.

Question 64

Describe the progression of heart failure

Answer 64

becomes more severe till death, and coronary events (e.g. MI) speeds up process of dying sudden death always a risk.