Cardiovascular Systems 13 - Heart Failure

Question 1

Define cardiac output

Answer 1

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

Question 2

Define ejection fraction

Answer 2

Stroke volume / end diastolic volume

Question 3

List the ranges for ejection fraction

Answer 3

> 55% normal
45-54% mildly reduced
30-44% moderately reduced
<30% severely reduced

Question 4

How can ejection fraction be measured?

Answer 4

Transthoracic echocardiogram

Question 5

Define heart failure.

Answer 5

• Inability of the heart to supply blood to the tissues sufficient to meet their metabolic needs
• Inadequacy of tissue perfusion
• Conjestion in the lungs and legs

Question 6

List the types of heart failure

Answer 6

• Left or right
• Chronic or acute
• Heart failure with reduced ejection fraction or with preserved ejection fraction

Question 7

Compare left and right sided heart failure

Answer 7

• Left sided is dysfunction in the left ventricle, right sided in the right side
• Both ejection or filling issue
• In left sided, blood backs up into the lungs causing congestion
• Right is due to increased afterload in the pulmonary circulation (pulmonary hypertension)
• Right side follows left side

Question 8

List some of the symptoms of left sided heart failure

Answer 8

• Respiratory symptoms (breathlessness, coughing, wheezing)
• Dizziness
• Cyanosis

Question 9

Compare acute and chronic heart failure

Answer 9

• Chronic heart failure has a slow onset

- Acute heart failure has a rapid onset

Question 10

Describe what happens in heart failure with reduced ejection fraction

Answer 10

• Abnormal systolic function
• Ventricles have impaired contraction, so though heart rate increases there is decreased cardiac output
• Weakness is caused by damage/destruction of the ventricular myocytes
• Weaker ejection leads to higher diastolic pressures

Question 11

Describe what happens in heart failure with preserved ejection fraction

Answer 11

• Abnormal diastolic function
• Normal ventricular contraction
• Increased stiffness of the ventricle, impaired relaxation or impaired filling
• EDV is reduced, the reduced stroke volume is masked when looking at ejection fraction.

Question 12

Briefly describe some epidemiological factors of heart failure

Answer 12

• Highest incidence age 60-64
• Risk increases with age then decreases
• Most common cause is coronary artery disease

Question 13

List the causes of heart failure

Answer 13

• Valve disease
• Ischaemic heart disease
• Myocardial infarction
• Hypertension
• Dilated cardiomyopathy
• Hypertrophic cardiomyopathy

Question 14

Describe how valve disease causes heart failure.

Answer 14

Hardening of valve(s) reduces the ventricular filling or ejection

Question 15

Describe how ischaemic heart disease causes heart failure

Answer 15

• Caused by narrowing of coronary arteries

- Ischaemia of the heart muscle

Question 16

Describe how myocardial infarction causes heart failure

Answer 16

Occlusion leads to death of heart muscle

Question 17

Describe how hypertension leads to heart failure

Answer 17

Hypertension increases the afterload, so the ventricle must work harder

Question 18

Describe how dilated cardiomyopathy leads to heart failure

Answer 18

Dilated left ventricular volume reduces ability to generate pressure, so the ejection reduces

Question 19

Describe how hypertrophic cardiomyopathy leads to heart failure

Answer 19

Increased left ventricular volume reduces internal ventricular volume and impedes filling

Question 20

List the clinical features of heart failure

Answer 20

• Breathlessness and fluid accumulation (orthopnoea, fatigue, paroxysmal nocturnal dysnoea)
• Anorexia/weight loss
• Pitting oedema
• Tachycardia
• Increased jugluar vein pressure
• Ascites

Question 21

List the investigations of heart failure

Answer 21

• x-ray
• Echocardiogram
• Ambulatory ECG
• Exercise test
• Angiogram
• BNP

Question 22

What are ascites?

Answer 22

An accumulation of fluid in the peritoneal cavity

Question 23

When is raised jugular venous pressure seen?

Answer 23

When in the right side of the heart, pressure increases causes pressures backing p into systemic veins

Question 24

When is B-type natriuretic peptide seen, and what is its function?

Answer 24

• Natriuresis is sodim excretion
• Released from ventricular myocytes in response to stretch
• Causes vasodilation, reduced aldosterone secretion, reduced sodium reabsorption, and inhibited renin secretion
• Results in reduced extracellular filling and reduced pressure

Question 25

List the lifestyle treatments of heart failure

Answer 25

Weight loss, stop smoking, exercise, less alcohol

Question 26

What medication is used for patients with heart failure?

Answer 26

• ACE inhibitor (reduces aldosterone production)
• Beta blockers reduces the blood pressure
• Spironolactone (diuretic)

Question 27

List the non-pharmacological treatments for heart failure

Answer 27

• Fluid control (haemofiltration, peritoneal dialysis, haemodialysis)
• Devices (intra-aortic balloon pumping, resynchronisation, total artificial heart)
• Surgical (coronary artery bypass graft, valve syrgery, transplantation)

Question 28

Write the equation for wall stress.

Answer 28

(Pressure x Radius)/ (2 x wall thickness)

Question 29

List the neural and hormonal changes following heart failure

Answer 29

• Production of natriuretic peptides is the beneficial response
• Renin angiotensin aldosterone system is the pathophysiological response

Question 30

How is heart failure classified?

Answer 30

Based on the physical limitations of the patients