Pathophysiology of Heart Failure * Flashcards
What are the 3 causes of heart failure?
- Impaired contractility
- Increased after load
- Impaired ventricular relaxation and filling
What happens when there’s reduction in EF with respects to systolic dysfunction?
Impaired contractility and excessive overload.
What happens when there’s preserved EF (diastolic dysfunction)?
Impaired diastolic relaxation
What else happens with reduced EF?
Decreased SV = higher ESV + normal venous return = EDV
What else happens with preserved volume?
There’s impaired ventricular relaxation, reduced filling, increase in stiffness and higher EDV.
The right ventricle is more susceptible to failure in situations where what happens?
Increased afterload
Right sided failure results in what?
Systemic congestion (veins) – swollen ankles and feet
How does the frank-starling compensatory mechanism work?
When there’s a reduced stroke volume, an increase in myofibril stretch occurs so that a greater SV is induced.
What does the adrenergic nervous system do in order to increase cardiac output
A fall in cardiac output is sense by baroreceptors causing an increase in heart rate and contractility. Vasoconstriction also occurs.
What is atrial natriuretic peptide?
It’s released by atrial cells in response to distension. Excretes sodium and water, allows vasodilation to occur, inhibits renin secretion, etc.
What’s B-Type Natriuretic Peptide?
It’s produced when ventricular myocardium is subjected to hemodynamics stress.
What does ventricular hyper trophy and remodelling do?
It will initially reduce wall stress and help maintain contractility. However it will eventually lead to stiffening
