Flashcards in CVS Session 11- Heart Failure Deck (14)
What are the three main pathophysiologies of heart failure?
Ischaemic heart disease
What is the relationship between end diastolic pressure and stroke volume?
The more the heart is filled, the higher the stroke volume, up to a point, according to starlings law. (More in=more out)
What is contractility?
It is the gradient of the end diastolic pressure- stroke volume graph
It is the force of contraction per given fibre length.
What happens to the force of contraction per given fibre length in HF?
It is less
What is congestive heart failure?
When there is heart failure of both the left and right heart?
When does right heart failure commonly occur? (2)
-as a result of left heart failure
-when there is a pulmonary problem.
How does left heart failure occur?
When there is excessive hypertrophy and then consequent failure of the left ventricle of the heart. This means it doesn't pump the blood that it should, therefore blood backs up to the LA and pulmonary veins.
What are 5 signs and symptoms of LHF?
-dyspnoea (worse on exertion and lying down)
-basal pulmonary crackles
Why does peripheral oedema occur in RHF?
Because RHF failure means that pulmonary resistance is increased, therefore blood backs up into the systemic venous system. This increases hydrostatic pressure of capillaries in the systemic circulation, causing fluid to move out of the capillaries and into the tissue spaces.
What are 5 signs and symptoms of RHF?
Describe the Renin-angiotensin-aldosterone system.
A drop in BP in heart failure causes the kidneys to release Renin because it thinks that there is an inadequate blood, therefore it sets up the dehydration system and increases sympathetic activity, ion resorption and water retention.
Renin causes angiotensin->ang. 1, which is then -> ang. 2 by ACE.
Ang. 2 is a powerful vasoconstrictor and promotes aldosterone release which causes salt and water retention, increasing blood volume.
How does the sympathetic nervous system increase the workload of the heart? (2)
-it stimulates alpha 1 receptors in blood vessels and therefore causes them to vasoconstrict, increasing blood pressure.
-it stimulates beta 1 receptors in the heart which causes chronotropy and inotropy.
What are the three main drugs given to treat heart failure? What do they do?
-ACE inhibitors- prevents the conversion of angiotensin 1 to 2 and therefore has a vasodilatory and diuretic effect; reducing the workload of the heart.
-beta blockers- prevent sympathetic innervation of the heart and blood vessels and therefore decrease the workload of the heart.
-diuretics- reduce blood volume and oedema by increasing fluid loss.