Pathology 2: Heart Failure Flashcards
Heart is similar to a pump, it’s composed of what components
- Control components
- Distribution components
What are the control components
- Myocardium
- Valves
- Conductive system
(Structure of the heart)
What are the distribution components
- Systemic circulation
- Pulmonary circulation
How does heart failure develops
Gradually and insidiously due to cumulative effects of disorders of various etiology
CO depends on what
SV x HR
What is SV
Amount of blood ejected from ventricle during systole
What is the equation of SV
SV = EDV-ESV
SV depends on what
- Preload
- After load
- Myocardial contractility
What is preload
- It’s the amount of blood ready to be pumped by the ventricle
- ventricular pressure at the end of diastole
- after the filling
(Same definition)
What is after load
- Pressure during ventricular systolic contraction
- during ejection of blood
What will happen to preload in heart failure
Decreased
What happens to after load in heart failure
Increased
When will SV increase
- Increase in preload
- Decrease in after load
- Enhanced contractility
What are the onset of heart failure
- Acute
- Chronic (congestive HF) (more common)
What are the sides involved in heart failure
Left and right side
What are the causes of left sided heart failure
- Hypertension
- Ischemic heart disease
- Aortic stenosis
- Moral incompetence
(1&2 are the most common)
How can ischemia causes heart failure
Atherosclerosis of coronary arteries =
less blood supply to cardiac muscle =
chronic ischemia of cardiac muscle
How can aortic stenosis causes heart failure
Narrowed aortic valve
= left ventricle will eject blood against increased resistance
= eventually will fail
How does mitral incompetence causes heart failure
Mitral valve isn’t closing properly
= back flow of blood during systole from left ventricle into left atrium
= left sided failure
What are the causes of right sided heart failure
1.COPD
2. LSHF (most common)
3. Pulmonary stenosis
4. Tricuspid stenosis
How can LSHF causes RSHF
When left side fails = pressure increase = blood accumulate in pulmonary congestion = pulmonary hypertension = edema = RSHF
How can COPD causes RSHF
any condition causes pulmonary fibrosis = fibrosis will cause pressure on pulmonary vasculature = pulmonary hypertension
What are the physiological compensatory mechanism
(Like exercising,etc)
- Dilation (to pump more blood)
- Increased heart rate
What is compensatory mechanism when there’s a pathological conditions
- Increased HR
- Dilation
- Hypertrophy
- Neuro-hormonal (RAAS)
What is the mechanism of dilation
Increased ventricle size = increase contraction force
What is the type of dilation in physiological condition
Active dilation
(The ventricle aren’t forced to dilate)
What is the type of dilation in pathological condition
Passive dilation
What is the end result of passive dilation
= gradual decrease of contraction force = strength of muscular contraction decrease = incomplete emptying
What happens when there’s increased heart rate in pathological conditions
The heart cannot empty it’s content completely = no sufficient time for complete emptying
What is the end result of hypertrophy
Muscles become too big for blood supply & nutrients = incomplete emptying = further heart failure = more dilation
What is the neurohormonal response in heart failure
= low CO
= + SNS & +RASS
= vasoconstriction + water & salt retention
= further stress on the failing heart
= further heart failure
What are the effects of heart failure
- Forward effects
- Backward effects
- impaired tissue perfusion
- venous congestion
- Edema
What are the effects of LSHF
- Impaired tissue perfusion
- Pulmonary congestion & Edema
What are the effects of RSHF
- Low output to lungs (insignificant unless due to LSHF)
- Systemic venous congestion
- Generalised Edema
What type of effects are more significant in RSHF
Backward effect
What are the causes of chronic HF
- Hypertension
- Ischemic heart disease
- COPD
- Valve disease
- Severe anemia
What are the effects of chronic HF
- Fully developed compensatory mechanism
- Generalised venous congestion
- Generalised Edema
What are the causes acute HF
- Coronary occlusion
- Pulmonary embolism
- Cardiac tamponade
- Malignant hypertension
- Acute mycocarditis
What are the effects HF
- No time for compensatory
- Multi - organ failure
- Acute pulmonary Edema