11. Heart Failure Flashcards
What happens to Starling’s law as cardiac failure becomes worse?
The heart no longer produces the same amount of force for a given level of filling
A patient complains of shortness of breath, a fast heart rate and fatigue on rest, what class of cardiac failure do you suspect he has?
Class 4 (the worst)
What is cardiac failure of both ventricles known as?
Congestive heart failure
What is the most common cause of right sided heart failure?
Secondary to left sided failure
When is shortness of breath worst in people suffering from left heart failure?
When laying down
Why can right sided heart failure lead to pitting at the ankles?
Right sided failure leads to increase in venous pressure
This leads to an increase in hydrostatic pressure at the venous end of s capillary bed
Hydrostatic pressure is now much greater than oncotic so water leaves causing peripheral oedema
What does renin do?
Catalyses angiotensin to angiotensin I
Where is renin released from?
Kidneys
What is ACE?
Converts angiontensin I to angiotensin II
What does angiotensin II do?
Vasoconstriction
Causes aldosterone release leading to water retention
What activates the renin angiotensin aldosterone system?
Hypotension in cardiac failure
Where are baroreceptors located?
Aortic arch
Carotid sinus
Hypotension detected by baroreceptors leads to what?
Medulla in brain activating sympathetic nervous response
Vasoconstriction via alpha 1 receptors (increases blood pressure hence increases preload and after load)
Activates the heart’s beta 1 receptors causing an increase in inotropy and chronotropy
What effect do ACE inhibitors have?
Vasodilatory and diuretic affect which lowers workload of the heart
Define heart failure
A state in which the heart fails to maintain adequate circulation for the body despite having adequate filling pressure
