Heart Failure

Question 1

What is heart failure?

Answer 1

The state in which the heart fails to maintain an adequate circulation for the needs of the body despite an adequate pressure.

Question 2

Give some causes of heart failure

Answer 2

Ischaemic heart disease
Hypertension
Dilated cardiomyopathy
High output heart failure - AV fistula or Paget’s disease (extra blood vessels)
Arrhythmia
Restrictive cardiomyopathy e.g. amyloidosis
Valvular/congenital heart disease

Question 3

What are the stages of heart failure?

Answer 3

I - no symptomatic limitations
II - slight limitations to physical activity, no symptoms at rest
III - limitations with less than normal activity. No symptoms at rest.
IV - can’t carry out physical activity without symptoms. May also have symptoms.

Question 4

What is normal cardiac output?

Answer 4

5L/min

Question 5

What is normal stroke volume?

Answer 5

75ml

Question 6

What is the normal ejection fraction?

Answer 6

Above or equal to 50%

Question 7

What affects cardiac output?

Answer 7

Venous capacity
Heart rate
Aortic and peripheral impedance
Myocardial contractility

Question 8

What are the causes of systolic dysfunction?

Answer 8

Increased left ventricular dysfunction
Decreased left ventricular cardiac output
Thinning of the myocardial wall (fibrosis and necrosis, activity of matrix proteinases)
Mitral valve incompetence
Neural-hormonal inactivity
Cardiac arrhythmia

Question 9

What structural changes can be seen in the heart in heart failure?

Answer 9

Reduced muscle
Uncoordinated or abnormal myocardial contraction
Changes to the ECM (increased collagen/slippage of fibre orientation )
Change in cellular structure and function (myocytolysis/vacuolation)
Myocyte hypertrophy
SR dysfunction
Change to calcium availability
Receptor regulation

Question 10

Describe how the sympathetic nervous system is activated in heart failure

Answer 10

Baroreceptor mediation.

Instant response

Question 11

What is the positive short term effect of sympathetic nervous system activation in heart failure

Answer 11

Increases cardiac output by improving contractility, arterial/venous contraction and causing tachycardia.

Question 12

What are the long term negative effects of sympathetic nervous system activation in heart failure?

Answer 12

Beta-adrenergic receptors downregulated or uncoupled
Noradrenaline increases cardiac hypertrophy and triggers myocyte apoptosis/necrosis via alpha-receptors
Induce upregulation of RAAS

Question 13

Describe briefly the renin-angiotensin-aldosterone system.

Answer 13

Angiotensinogen to angiotensin I by renin
Angiotensin I to angiotensin II by ACE
AT1R is detrimental
AT2R causes water retention and aldosterone secretion, increases NO production.

Question 14

What effects does AT1R activation have on the vasculature?

Answer 14

Atherosclerosis
Vasoconstriction
Vascular hypertrophy
Endothelial dysfunction

Question 15

What effects does AT1R activation have on the heart?

Answer 15

Left ventricular hypertrophy
Fibrosis
Remodelling
Apoptosis

Question 16

What effects does AT1R activation have on the kidney?

Answer 16

Decreased GFR
Increased proteinuria
Increased aldosterone release
Glomerular sclerosis

Question 17

What clinical problems can be caused by AT1R activation in the long term?

Answer 17

Stroke
Hypertension
Heart failure
Myocardial infarction
Renal failure

Question 18

What are the effects of angiotensin II activation?

Answer 18

Vasoconstriction
Increased left ventricular hypertrophy and myocyte dysfunction
Increase aldosterone release
More sodium and water retention
Stimulate thirst by central activation

Question 19

What is the function of natriuretic hormones activated in heart failure?

Answer 19

Decreases sodium reabsorption
Inhibits secretion of renin and angiotensin
Balance the effects of RAAS on vascular tone and sodium/water balance

Question 20

What causes the release of natriuretic hormones in heart failure?

Answer 20

Stretch of the arteries/veins/vasculature in the brain

Question 21

How can anti-diuretic hormone cause hyponatraemia?

Answer 21

Water is reabsorbed in excess of sodium.

Can also be due to excessive water consumption

Question 22

What is the function of endothelin?

Answer 22

Systemic and renal vasoconstriction via autocrine action, activating RAAS.

Question 23

What stimulates the release of prostaglandin E2/I2 in heart failure?

Answer 23

NA

RAAS

Question 24

What is the function of prostaglandin E2/I2 in heart failure?

Answer 24

Vasodilate afferent renal arterioles

Question 25

What drugs can block the action of prostaglandin E2/I2?

Answer 25

NSAIDs e.g. aspirin

Question 26

What effect can alpha-TNF have in heart failure?

Answer 26

Decreases myocardial function May stimulate NO synthase Role in cachexia

Question 27

How does changes to vascular tone exacerbate the clinical features of heart failure?

Answer 27

Decreased skeletal muscle tone Decreased skeletal muscle mass including the limbs and respiratory muscles (can cause death) Abnormal structure and function Fatigue and exercise intolerance

Question 28

How can heart failure precipitate renal failure?

Answer 28

GFR initially maintained by haemodynamic changes in the glomerulus Increased sodium/water retention. Neurohormonal action. Decreased GFR in severe heart failure which causes increased serum urea and creatinine Can be exacerbated by treatment which inhibits angiotensin II

Question 29

Who is left ventricular diastolic dysfunction most commonly seen in?

Answer 29

Elderly Females History of hypertension, diabetes and/or obesity

Question 30

What are the problems in the heart when there is left ventricular diastolic dysfunction?

Answer 30

``` Low left ventricular compliance Impaired relaxation Impaired left ventricular filling Decreased CO Triggers neurohormonal activation ```

Question 31

What are the different types of heart failure?

Answer 31

``` Right sided heart failure Left sided heart failure Biventricular (congestive) heart failure Systolic heart failure Diastolic heart failure ```

Question 32

How can diastolic heart failure be caused by systolic heart failure?

Answer 32

Hypertrophy with disorganisation or MI which causes fibrous tissue formation

Question 33

What are the potential causes of right heart failure?

Answer 33

``` Chronic lung disease (most common) Pulmonary embolism Pulmonary hypertension Pulmonary/tricuspid valvular disease ASD/VSD Isolated right ventricular hypertrophy ```

Question 34

What are some symptoms of right heart failure?

Answer 34

``` Fatigue Dyspnea Anorexia Nausea (may be due to ascites Increased JVP Hepatic enlargement Ascites Pitting oedema Pleural effusion ```

Question 35

How can right heart failure precipitate a DVT?

Answer 35

Systemic congestion which increases stasis in the veins and therefore increases the risk of a DVT

Question 36

What are the principals of treating heart failure?

Answer 36

Correct the underlying cause Pharmacological treatments Non-pharmacological treatments Treat complications, associated conditions and cardiovascular risk factors.

Question 37

What lifestyle modifications could you suggest to someone with heart failure?

Answer 37

Reduce salt intake Decrease alcohol intake Increase aerobic exercise Decrease blood pressure

Question 38

What are the pharmacological treatments for heart failure

Answer 38

``` Diuretics ACEi/ARB Nitrates Beta blockers Spironolactone/amiloride Antiarrhythmics Inotropes (only in an acute setting) ```

Question 39

Suggest a form of cardiac surgery which can be used to treat heart failure

Answer 39

Total heart transplantation Mechanical assist devices Underlying cause - valve surgery/revascularisation Implantable pacemakers/defibrillator