Heart Failure COPY Flashcards
Label the parts of the heart on the diagram
Why does tricuspid valve regurgitation cause venous congestion?
The tricuspid valve normally allows the unidirectional flow of venous blood from the right atrium into the right ventricle.
If it is damaged, when the right ventricle contracts, blood will be regurgitated back into the right atrium and back into the SVC and IVC and into the venous system. These veins are valveless, so allow the back flow of venous blood.
Name the main functions of the heart
Delivery of deoxygenated blood to the lungs for oxygenation
Delivery of oxygenated blood to the body
Delivery of nutrients
Removal of waste
Describe the main layers of the heart wall
- Endocardium: squamous cell epithelium
- Myocardium: involuntary striated muscle cells and collagen
- Epicardium
- Pericardium: double membraned sac that fixes the heart in place, lubricates and prevents infection.
What are the 2 main ways in which heart valves usually fail?
- Stenosis: calcification of the valves, causing them to allow less blood through so the ventricles must contract harder to push the blood through → ventricular hypertrophy→ HF.
-
Regurgitation: unidirectional flow of blood is lost. When the ventricles contract, blood is pushed back into the atria as well as the arteries causing congestion. (Left: pulmonary congestion; Right: venous congestion)
- → Dilation of blood vessels and ventricles (loss of muscle tone) → HF.
What is the effect of atrial fibrillation on the cardiac cycle?
Passive filling of the ventricles continues, however there is a loss of atrial ‘kick’ which is needed to fill the ventricles against the rising pressure from passive filling. (30% lost)
This causes under-filling of the ventricles and a loss of cardiac output.
What is systolic heart failure?
Loss of power of contraction of the ventricles
What is diastolic heart failure?
Relaxation of the ventricles in diastole is impaired, therefore the ventricles do not passively fill as effectively → less blood to be pumped out during systole.
What is the ejection fraction?
The percentage of blood ejected from the ventricles during ventricular systole from the total blood that was in there at the beginning of systole.
How do you calculate cardiac output?
SV x HR = CO
(70ml x 70bpm = 4900ml)
Name the 3 most common causes of heart failure
Coronary Artery Disease:
- Post MI
- Chronic ischaemia
Hypertension:
- Struggling against high afterload
Valvular disease:
- Regurgitation of a valve: volume overload (congestion)
- Stenosis of a valve: extra force needed to overcome
Name other causes of heart failure
- Cardiomyopathies
- Arrhythmias
- Drugs (anti-arrhythmics, cytotoxics)
- Toxins (alcohol, cocaine, mercury)
- Endocrine (diabetes, thyroid disease, adrenal disease)
- Nutritional (thiamine deficiency, obesity)
- Infiltrative (sarcoidosis, amyloidosis, haematochromatosis)
- Infective (HIV)
What is high output cardiac failure?
Name 3 causes
- Pregnancy
- Hyperthyroidism
- Anaemia
More common in younger people.
Caused by higher demand on the heart (e.g. anaemia- lack of oxygen means the heart has to work harder to deliver oxygen to tissues)
Name some symptoms of left-sided heart failure
- Dyspnoea
- Fatigue
- Orthopnoea
- Paroxysmal nocturnal dyspnoea
- Nocturnal cough (+/- pink, frothy sputum)
Most symptoms are due to backlog of blood into the lungs (higher preload)
Name some symptoms of right-sided heart failure
- Nausea
- Anorexia
- Reduced mobility
Symptoms caused by venous congestion in the body
