Cardiovascular System - Lec 7 Flashcards
Explain what’s heart failure
Inability of heart to pump in an optimum manner needed by the tissues, and this can be due to many differnt diseases
There are 2 types
- Heart failure with preserved ejection fraction (diastolic failure)
- HsRt failure with reduced ejection fraction (pumping function of heart impaired, ie. systolic dysfunction
How do you image heart failure for analysis
Imaging features like changes in stroke volume and ejection fraction and structural changes in chambers
Explain in more detail in regards to heart failure with reduced ejection fraction
Systolic dysfunction, abnormal pumping (contracting)
This type is the result of decreased contractibility of the heart (due to injury to the myocardium) or increased afterload (due to high blood pressure or obstruction to outflow)
To compensate for increased afterload, the walls of chambers must thicken and this has an adverse effect
Explain in more detail in regards to heart failure with preserved ejection fraction
Diastolic function of heart is impaired, failure of heart relaxation
Can be due to
- myocardial ischasmia (bad blood supply to myocardium will prevent good relaxation)
- ventricular hypertrophy (thickening of ventricular muscle thus affecting function - can be due to increased in afterload)
- increased stiffness of myocardium
Explain the difference between left side and fright sided heart failure
Left side
- left ventricle is one which is failing, which is often do to myocardial infarction.
- left is for systemic right, so high pressure and is more suspectible for damage
- congestion in lungs
Right side
- the right ventricle is failing, commonly due to left sided heart failure and can also be due to respiratory disease
- congestion in peripheral tissues
What’s a sign or symptom that is due to heart failure?
Oedema and congestion
Explain the formation of an oedema and congestion related to heart failure
Heart doesn’t empty effectively (heart failure), so its harder to fill the chambers with blood = increase filling pressure and venous pressure (due to back pressure). This causes a back pressure throughout the vascular system, and as there’s now very high pressures in the capillary, water will force bill be moved out due to gradient and into tissues (oedema)j
We’ll find that:
- left heart failure has veins (pulmonary veins) that drain the lungs and so cause congestion in the lungs (pulmonary oedema)
- right heart failure has veins (systemic veins ie IVC) supplying right side of heart and draining the extremities so congestion will develop in abdomen, ankles (peripheral oedema)
How is heart failaure detected?
Enlargement of the Heart on a PA
- dilation = overall increase in diameter (dilating cardiomyopathy)
- hypertrophy = increase in thickness of the walls (less space to accomodate for blood within ventricles)
Explain what’s cardiomyopathies that’s relevant to the development of heart failure
Cardiomyopathies is a term given to a group of diseases that cause heart failure (Heart enlargement)
The categorised diseases affect the myocardium by affecting the size of the heart causing dilation of hypertrophy
Describe dilating cardiomyopathy
It’s the stretching of heart due to weakened muscle or excessive blood in ventricles (REDUCED EJECTION FRACTION)
The causes include:
- idiopathic (no known cause)
- coronary artery disease (muscle weakened)
- valvular or hypertensive disease (heart over load)
- infections
- endocrine diseases
- haematological diseases (sickle cell anaemia)
- alcoholism
Wall of ventricle will be thin due to weakening of heart muscle (the walls become wider and more apart) and this abnormal position of the walls will affect the function of the valves and allow backflow back into the ventricle
Describe hypertrophy cardiomyopathy
Increase in size and number of muscle cells in heart, which can occur due to the heart trying to pump against increased resistance.
This causes decreased ventricular size (thickening of wall) and so the amount of blood held decreased (hence, diastolic failure where PEF).
Thickening of wall can be due to increase work load as a result:
- outflow obstruction (Narrow opening increase workload)
- hypertension
- endocrine diseases
- diastolic failure (relaxation)
- myocardial ischaemia
MUCH HARDER TO DETECT OF PLAIN RADIO than dilation
Explain what’s a valvular heart disease
Can be divided into 2 type sod probelms
- narrowing (stenosis) increases afterload = hypertrophy
- valve incompetence (regurgitation) = backflow
Further explain what’s stenosis in valvular heart disease
Obstruction of blood flow that makes it hard to pump blood from ventricle, therefore, decreased blood flow through valves.
Increases resistance to outflow due to the obstruction (ie. narrowing, or even aortic valve stenosis), therefore, the myocardium hypertrophies in response as it’s working harder to fight the resistance
There will be backpressure throughout the vascular circuit which can cause an oedema
Eventually systolic dysfunction occurs, where contraction of heart is impaired as the myocardium can no longer maintain high workload to maintain function
Further explain what’s regurgitation in valvular heart disease
Referred to as valvular icompetence as it is caused by a disease valve or the valves supporting structures.
Usually occurs due to infection, and it causes a large increase in end diastolic (relaxed ventricle) volume as blood flows backwards through the incompetent valve REDUCED EJECTION FRACTION
Explain how valvular abnormalities are analysed
Echocardioradiogrpahy - examine valve motion, chamber enlargement (due to overload)
Doppler - used to measure the pressure gradient across the valve
Cardiac mri and ct
Plain rad - shows hypertrophy of chambers (due to overload)
