What are the main causes of heart failure (6)
- congenital
- degenerative valve disease
- cardiomyopathy
- Endocarditis
- pericardial disease
- rate/rhythm abnormalities
What is concentric hypertrophy?
An increase in thickness of the left ventricle
What is eccentric hypertrophy?
A dilation in the left ventricular chamber
What is restrictive hypertrophy?
Stiffness in the walls of the left ventricle
How does cardiomyopathy lead to heart failure?
A cardiomyopathy/disease of the heart muscle, will cause the heart to become less efficient as the muscle fails. Stroke volume will reduce and the cause the ventricle to dilate and become thinner.
How can pericardial effusion cause heart failure?
The pericardial effusion will affect the heart from filling adequately and so contractility is reduced and the heart is unable to pump as much blood around the body
What type of hypertrophy will volume loading of the heart cause?
dilated so eccentric
What type of hypertrophy will pressure loading of the heart cause?
concentric as it thins the walls
How does the body respond to cardiac failure? (6)
- low cardiac output means blood pressure has reduced
- Baroreceptors detect less stretch
- SNS activated
- RAAS activated
- ADH secretion
- eventually cardiac enlargement
Describe the vicious cycle of heart failure (5)
- Heart failure causes reduced cardiac output
- compensatory mechanisms cause ADH secretion
- ADH causes fluid retention
- Preload and after load increases
- This aids the progress of heart failure
What are the general clinical signs of heart failure?
- Tachycardia
- Cardiac enlargement
- Decreased urine production
- cyanosis
- decreased exercise tolerance
What is a specific signs of right sided heart failure?
peripheral oedema
What are some specific signs of left sided heart failure? (3)
- pulmonary oedema
- coughing
- dyspnea
What are the main treatment options for heart failure? (4)
- digoxin
- Beta-blockers
- ACE inhibitors
- Calcium channel blockers
Why might a drug fail to be effective?
- dose too low
- administration failure
- tachyphylaxis
What is tachyphylaxis?
rapidly diminishing response
How can traumatic reticulates develop into pericarditis in cows? (5)
- sharp objects penetrates the reticulum
- reticulum contractions causes the movement of the object
- infection spreads along the object into the abdomen
- abscesses can develop which can reach the pericardium
- or the object can move and penetrate the pericardium
Is it possible for the pericardium to be removed following infection or disease?
Yes
