Heart failure

Question 1

What is heart failure?

Answer 1

A state that develops when the heart fails to maintain an adequate cardiac output to meet the demands of the body

Question 2

What causes heart failure?

Answer 2

Results from any structural or functional abnormality that impairs the ability of the ventricle to eject blood (systolic HF) or fill with blood (diastolic HF)

Question 3

At rest in a typical adult what is normal cardiac output?

Answer 3

70mls/kg/min

Question 4

List 3 factors which affect stroke volume

Answer 4

Contractility
Preload
Afterload

Question 5

How does an increase in heart rate affect the cardiac output?

Answer 5

Causes an increase

Question 6

In which phase does filling of the heart occur?

Answer 6

Diastole

Question 7

In which phase does contraction of the heart occur?

Answer 7

Systole

Question 8

What does excessive high heart rate cause?

Answer 8

Excessively high HR results in a decrease in the amount of time allowed for the ventricles to fill in diastole which causes SV and, thus CO to fall

Question 9

Define contractility

Answer 9

The intrinsic ability of the myocardium to contract

Question 10

What is preload?

Answer 10

The volume of blood or stretching of cardiomyocytes at the end of diastole prior to the next contraction

Question 11

What is afterload?

Answer 11

The resistance/end load against which the ventricle contracts to eject blood

Question 12

When does preload increase?

Answer 12

When there is an increase in blood volume and vasoconstriction

Question 13

What decreases preload?

Answer 13

Blood volume loss and vasodilatation

Question 14

What does the frank starling law state?

Answer 14

An increase in volume of blood filling the heart stretches the heart muscle fibres causing greater contractile forces which, in turn, increases the stroke volume
Is true only up to a certain point… at some stage the fibres become over-stretched and the force of contraction is reduced

Question 15

What does vasodilatation do to afterload?

Answer 15

Decreases

Question 16

What does hypertension and vasoconstriction do to afterload?

Answer 16

Increases

Question 17

What happens to cardiac output as afterload increases?

Answer 17

Decreases

Question 18

State the 2 types of low output heart failure

Answer 18

Systolic heart failure

Diastolic heart failure

Question 19

What is high output heart failure?

Answer 19

Occurs in the context of other medical conditions which increase demands on cardiac output, causing a clinical picture of HF
The heart itself is functioning normally but cannot keep up with the unusually high demand for blood to one or more organs in the body

Question 20

What can cause high output heart failure?

Answer 20

Thyrotoxicosis, profound anaemia, pregnancy, paget’s disease, acromegaly, sepsis

Question 21

What is systolic heart failure?

Answer 21

Where the heart has become weak

Progressive deterioration myocardial contractile function

Question 22

List 3 causes of systolic heart failure

Answer 22

Ischemic injury
Volume overload
Pressure overload

Question 23

What is diastolic heart failure?

Answer 23

Inability of the heart chamber to relax, expand and fill sufficiently during diastole to accommodate an adequate blood volume

Question 24

List the causes of diastolic heart failure

Answer 24

Significant left ventricular hypertrophy (LVH) e.g HCM
Infiltrative disorders
Constrictive pericarditis
Restrictive cardiomyopathy

Question 25

State some other causes of heart failure

Answer 25

``` Coronary Heart Disease Hypertensive Heart Disease Valvular Heart Disease Myocardial Disease/ Cardiomyopathies Congenital Heart Disease ```

Question 26

Define cardiomyopathy

Answer 26

Diffuse disease of the heart muscle leading to functional impairment

Question 27

List the 3 types of cardiomyopathy

Answer 27

Dilated cardiomyopathy Hypertrophic cardiomyopathy Restrictive cardiomyopathy

Question 28

Describe the pathophysiology of heart failure

Answer 28

Pump failure leads to reduced SV and CO. Compensatory mechanisms kick in to maintain arterial pressure and perfusion of vital organs

Question 29

List some compensatory mechanisms of heart failure and state what they do

Answer 29

The Frank Starling mechanism: vasoconstriction, increased venous return to the heart, increased preload, heart muscle fibres stretch, enhanced contractility Myocardial structural change: Augmented muscle mass (hypertrophy) with or without cardiac chamber dilatation Activation of neurohormonal system: Release of Noradrenaline – increases heart rate and myocardial contractility. Causes vasoconstriction Release of ANP/BNP Activation of renin-angiotensin – aldosterone system

Question 30

What is the problem with compensatory mechanisms of heart failure?

Answer 30

They may worsen the heart failure

Question 31

What can pressure overload cause?

Answer 31

Concentric left ventricular hypertrophy Augmented muscle may reduce the cavity diameter Cross sectional areas of the myocytes are increased

Question 32

What can volume overload cause?

Answer 32

Chamber dilatation with increased ventricular pressure Deposition of new sarcomeres Increased cell length and width Muscle mass and wall thickness are increased in proportion to chamber diameter

Question 33

Describe some clinical types of heart failure

Answer 33

Left sided, right sided and biventricular failure Acute and chronic heart failure Compensated and decompensated heart failure

Question 34

Describe left sided heart failure

Answer 34

Blood backs up progressively from the left atrium to the pulmonary circulation

Question 35

What are the causes of left sided heart failure?

Answer 35

Ischaemic heart disease Hypertension Valvular heart disease Myocardial disease

Question 36

How does left ventricular failure affect the lungs?

Answer 36

Pressure in the pulmonary veins is transmitted retrogradely to the capillaries and arteries This leads to pulmonary congestion and oedema

Question 37

What problems are caused by heavy/wet lungs from left ventricular failure?

Answer 37

Orthopnoea Paroxysmal nocturnal dyspnoea Dyspnoea

Question 38

How does left ventricular failure affect the kidneys?

Answer 38

Decreased cardiac output Reduction in renal perfusion Activation of renin - angiotensin – aldosterone system Retention of salt and water with consequent expansion of interstitial fluid and blood volumes

Question 39

How does left ventricular failure affect the brain?

Answer 39

``` Hypoxic encephalopathy Irritability Loss of attention Restlessness Stupor and coma ```

Question 40

Describe right sided heart failure and its causes

Answer 40

Right sided HF due to significant pulmonary hypertension due to increased resistance within the pulmonary circulation Usually as a result of respiratory disease e.g. COPD or pulmonary emboli Other causes: Valvular heart disease Congenital heart disease

Question 41

What causes biventricular failure (Congestive cardiac failure)?

Answer 41

Either due to the same pathological process on each side of the heart OR A consequence of left heart failure leading to volume overload of the pulmonary circulation and eventually the right ventricle causing right ventricular failure

Question 42

List the main clinical presentations of heart failure

Answer 42

``` Dyspnoea Orthopnoea, paroxysmal nocturnal dyspnoea Oedema Hepatic congestion Ascites Fatigue Weakness ```

Question 43

Describe the new york classification of heart failure

Answer 43

Class I: No limitation of physical activity Class II: Slight limitation of ordinary activity Class III: Marked limitation, even during less-than-ordinary activity Class IV: Severe limitation with symptoms at rest

Question 44

List the symptoms of acute pulmonary oedmea

Answer 44

``` Acute Breathlessness Pallor Cyanosis Sweating Rapid Pulse Hypoxia Crackles in Lungs ```

Question 45

List the current drug treatments for heart failure

Answer 45

``` Diuretics SA node blockades Beta blockers Aldosterone antagonists ARNI ACE inhibitors ```

Question 46

Give an example of a loop diuretic

Answer 46

FRUSEMIDE

Question 47

How do loop diuretics work?

Answer 47

Inhibit Na+ re-absorption from the proximal tubule | K+ loss from distal tubule

Question 48

If used incorrectly what can loop diuretics cause?

Answer 48

Electrolyte abnormalities | Hypovolaemia and diminished renal perfusion

Question 49

Give an example of a mineralocorticoid receptor antagonist

Answer 49

Spironolactone

Question 50

How do mineralocorticoid receptor antagonists work?

Answer 50

Acts on distal tubule Promotes Na+ excretion and K+ re-absorption Reduces hypertrophy and fibrosis

Question 51

How do ACE inhibitors work?

Answer 51

Act on activated renin - angiotensin system Given orally in small doses with slow titration Block production of angiotensin: Vasodilatation BP lowering Reduce cardiac work

Question 52

Give an example of an ACE inhibitor

Answer 52

Ramipril

Question 53

Give an example of a beta blocker

Answer 53

Bisoprolol

Question 54

How do beta blockers work?

Answer 54

Block the action of adrenaline and noradrenaline on adrenergic beta receptors Slow HR, reduce BP

Question 55

What does digoxin do?

Answer 55

Action: Increases myocardial contractility Slows conduction at the AV node (use in AF) Excreted by kidney - Toxicity important

Question 56

When is digoxin given?

Answer 56

Acute HF especially in AF | Chronic HF in selected cases

Question 57

State the immediate treatment of acute pulmonary oedema

Answer 57

High flow oxygen IV Morphine IV Nitrates IV Frusemide