Congestive Heart Failure

Question 1

What is the definition of congestive heart failure?

Answer 1

The heart fails when it is unable to eject blood delivered to it from the venous system

Question 2

What are the 4 main types of congestive heart failure?

Answer 2

Left sided heart failure
Right sided heart failure
Biventricular heart failure
High-output heart failure (least common)

Question 3

What is the definition of left sided heart failure and what causes it?

Answer 3

When the left ventricle does not efficiently pump blood into the aorta. This causes a backflow of blood causing pulmonary oedema. The causes can be split into systolic and diastolic.
Systolic heart failure is mainly caused by ischamia from atherosclerosis.
Diastolic heart failure is mainly from stiff ventricle that cannot relax in diastole

Question 4

What are the causes of left sided systolic heart failure?

Answer 4

Mainly ischaemia from atherosclerosis

Can be post MI, myocarditis or dilated cardiomyopathy

Question 5

What are the causes of left sided diastolic heart failure?

Answer 5

This is less common than systolic heart failure
It is caused by decreased compliance of the left ventricle so it does not fill in diastole
This is most commonly caused concentric ventricular hypertrophy as a result of hypertension
Other causes are AV stenosis and hypertrophic cardiomyopathy

Question 6

What are the gross and microscopic findings in left heart failure?

Answer 6

Lungs are heavy and congested with a pink frothy transudate (oedema)
The alveolar macrophages often contain haemosiderin producing rust coloured sputum

Question 7

Why do left heart failure patients sometimes produce a rust coloured sputum?

Answer 7

This implie that under the pressure the blood capillaries have burst allowing red blood cells into the alvoli to be phagocytosed. The excess iron in the macrophages binds to ferritin which degrades into haemosiderin which is rust coloured.

Question 8

What are the main clinical and leb findings in left heart failure?

Answer 8

Dyspnoea caused by the oedema
Pulmonary oedema causing an expiratory wheeze
Bibasilar inspiratory crackles caused by the odema
Rust coloured sputum from haemosiderin in the macrophages
Chest radiograph signs of pulmonary odema
S3 and S4 sounds
Functional MV regurgitation (stretching of valve ring causes regurge)
Paraoxysmal noctural dyspnea
Increase serum brain natriuretic peptide

Question 9

Why do you get dyspnea with pulmonary oedema?

Answer 9

Interstitual fluid stimulates the juxtacapillary receptors that are inervated by the vagus nerve, this means that the vagus nerve is activated causing prevention of full inhalation

Question 10

What are the chest radiograph findings of pumonary oedema?

Answer 10

Upper lobe congestion (early on)
Perihilar congestion (bat wing configuration)
Fluffy alveolar infiltrates
Kerley lines (septal oedema)
Air bronchograms (air visible in the brinchus or small airways because fluid surrounds the airways)

Question 11

Why does pulmonary oedema cause paroxysmal nocturnal dyspnea?

Answer 11

When lying supine there is no effect of gravity so fluid move back into the vascular compartment. This causes increased venous return to the right heart and then to the failed left heart. The failed left heart causes a backflow as it cannot handle the excess and blood backs up in the lungs. This caues dyspnea and pulmonary odema. Relived by standing or pillows (orthopnea)

Question 12

Why does serum natriuretic peptide increase in left heart failure?

Answer 12

It is secreteted by the ventricles when they are volume overloaded. Serum atrial natriuretic peptide also increases because the atria are stretched by backflow

Question 13

What are the main causes of right heart failure?

Answer 13

Increased afterload mainly caused by left ventricular hypertrophy
Decrease in RV afterload e.g. infarction, myocarditis
RV non compliant e.g. concentric right ventricular hypertrophy

Question 14

What are the clinical and lab findings of right heart failure?

Answer 14

Raised JVP caused by backflow of blood
Functional TV regurge caused by stretching of TV
Right sided S3 and S4 sounds due to RV volume overload
Painful hepatomegaly caused by centrilobular haemorrhagic necrosis - backflow of blood causes hepatic cell necrosis - this causes increased ALT and AST
Increase in pressure can pass into the portal vein and cause ascites
Painful pitting oedema
Cyanosis of the mucous membranes due to blood moving slowly and tissues have taken up more O2 causing low saturations

Question 15

What is high output heart failure?

Answer 15

It is heart failure where the caridac output is increased compared to normal

Question 16

What are the causes of high output heart failure?

Answer 16

Increase in stroke volume e.g. hyperthyroidism
Decrease in blood viscocity e.g. severe anaemia causes increased venous return
Vasodilation of arterioles that cause venous return e.g. thiamine deficeiency
Arteriovenous fistula e.g. from trauma

Question 17

What are the nonpharmacologic treatments for congestive heart failure?

Answer 17

Restricting sodium and water which are both increased because of decreased cardiac output and renal retention.

Question 18

What are the treatments for systolic heart failure?

Answer 18

It is treated by drugs that decrease the workload of the heart. This is done by decreasing the preload and afterload.
First line treatment is an ACE inhibitor or angiotensin II receptor inhibitor
Diuretics can also be used to decrease preload
Beta blockers decrease sympathetic tone that decrease O2 consumption by the myocardial muscle.