Pathophysiology Of Heart Failure Flashcards
What pressure needs to be exceeded (left ventricular end diastolic pressure) for pulmonary oedema to develop?
25 mmHg
When right ventricular end diastolic pressure exceeds this value asides and pleural effusion develop
10-15mmHg
Define backward failure
Also known as congestive heart failure. Congestion and/ or oedema develop and is the most common type of heart failure in dogs and cats
Forward failure define
Poor peripheral perfusion at rest or with exercise. Less common on dogs and cats
Which is activated first? Baroreceptors or RAAS?
Baroreceptors kick in in response to acute blood loss. RAAS system takes longer.
What does chronic elevated sympathetic tone do to your heart?
Promote arrrhumias, causes cell death, myocardial death.
Receptors get unregulated when you block them. There with beta blockers then must wean off slowly due to up regulation.
When would you use beta blockers?
Pulmonic or aortic sternosis
Digoxin rests Baroreceptor response.
What speed would you expect blood to pass with aortic sternosis
Over 80mm of mercury
Difference between concentric and eccentric hyperteophy
Sodium nitroprusside is used in cases which are not responding to initial acute heart failure management. How does it help?
Decreases afterload
What receptors does noradrenaline act on?
Cardiac beta receptors to increase cardia output
Alpha adrenergic receptors to maintain BP
Activates RAAS
What are the main drivers of RAAS?
- Noradrenaline
- decreased delivery of sodium to the macula densa as a result of decreased renal blood flow.
What does angiotensin two do?
Causes Vasoconstriction
Acts on adrenal glands to produce more aldosterone (more retention of water by retention of sodium which increases intravascilar volume)
Increase sympathetic nervous system
