Cardiac failure Flashcards
What is heart failure
Failure of the heart as a pump to meet the circulatory needs
After a myocardial infarction, what types would the heart failure be
Chronic or acute
What is heart disease precipitated by
Pregnancy
ANaemia
Hyper and hypothyroidism
Fluid retaining drugs like glucocorticoids and NSAIDs
How does hyperthyroidism lead to heart disease
Can over stimulate the heart which would lead to heart failure
How does hypothyroidism
Can under stimulate the heart which would lead to heart failure
What does ischaemic heart disease affect
Impaired muscle function ie preload, after load, and muscle contractility
What is ischeamic heart disease
Coronary heart disease
How is hypertension a risk for chronic heart failure
- For the increase in after load, you get left ventricular hypertrophy
- This means the heart is less efficient at generating force
To compensate for circulatory failure, what gets activated in the body
- Sympathetic nervous system
- Renin-angiotensin-aldosterone system
- ADH
- Atrial Natriuretic Peptide (ANP)
How does the sympathetic nervous system compensate for circulatory failure
Acts on beta adrenoceptors which keeps the heart going
How does ADH compensate for circulatory failure
Conserves fluid which would lead to fluid overload
How does ANP compensate for circulatory failure
Released by failing atria which would lead to the excretion of sodium
What do the macula densa detect
Low sodium and low blood pressure and volume
What do the macula densa release
Renin
How does the renin-angiotensin system make heart failure worse
- Renin chops up angiotensinogen to make angiotensin 1. This is chopped up to angiotensin 2 by angiotensin converting converting enzyme
- From angiotensin 2, this leads to vasoconstriction and augments the sympathetic nervous system
- It also acts on adrenal glands to release aldosterone which retains sodium and causes potassium loss
=ALl of these leads to increased effort needed by heart which is bad because there is higher pressure and more fluid
What does increased vasoconstriction lead to
Increased resistance which leads to impaired renal function and so further renin angiotensin cycle
When does left-sided hypertension usually occur
Often after hypertension
What does poor output from the left hand side lead to
Increase in left atrial and pulmonary venous pressure with pulmonary oedema
What does right sided failure often lead to
Lung disease
Pulmonary valvular stenosis
How is biventricular failure caused
Left ventricular failure leads to pulmonary congestion which may lead to right ventricular pressure
-Or ischaemic heart disease
Symptom of pulmonary oedema
Shortness of breath (drowning sensation)
What causes paxosymal nocturnal dysponoea
When a patient is lying down, it promotes venous return and so in those with oedema, the blood rushes back to heart and lungs
What is peripheral oedema associated with
Right hand side failure
What is the value of ejection fraction which is consistent with heart failure
45%
