Cardiovascular Pathology 2 Flashcards
What is the definition of heart failure / congestive cardiac failure (CCF)?
Inability of the heart to pump enough blood needed to meet the metabolic demands of the tissue
it can occur insidiously or suddenly
What causes heart failure to occur insidiously or suddenly?
Insidious:
- cumulative effects of chronic workload
- hypertension and valve diseases
Sudden:
- acute haemodynamic stress
- fluid overload and large myocardial infarction
What are the three categories that can cause increased cardiac work?
- Hypertension causes pressure overload
- valvular disease causes pressure and/or volume overload
- myocardial infarction causes regional dysfunction with volume overload
What does an increase in cardiac work lead to?
Increased cardiac work leads to increased wall stress
this leads to cell stretch (enhanced contractility - Frank-Sterling mechanism)
this leads to hypertrophy and/or dilation
what is hypertrophy and/or dilation characterised by?
- Increased heart size & mass
- increased protein synthesis
- induction of immediate-early genes
- induction of fetal gene program
- abnormal proteins
- fibrosis
- inadequate vasculature
what does hypertrophy and/or dilation lead to?
Cardiac dysfunction
(left-sided heart failure)
what is cardiac dysfunction characterised by?
- Heart failure (systolic / diastolic)
- arrhythmias
- neurohumoral stimulation
what is meant by neurohumoral stimulation in cardiac dysfunction?
Release of norepinephrine:
- increases heart rate and myocardial contractility
activation of renin-angiotensin-aldosterone system:
- adjusts fluid volume
release of atrial natriuretic peptides:
- Adjusts fluid volume
What are other causes of CCF that cause increased cardiac work?
- Hyperthyroidism
- beriberi
- anaemia
- congenital heart diseases
What are the clinical effects of left sided heart failure due to?
- Low cardiac output and hypoperfusion of tissues
- pulmonary congestion
What are the symptoms of left heart failure (congestion)?
- Dyspnea
- orthopnea
- paroxysmal nocturnal dyspnea (PND)
- blood tinged sputum
- cyanosis
- elevated pulmonary “wedge” pressure (PCWP)
what are the consequences of left sided failure producing a low cardiac output?
There is reduced kidney perfusion
- pre-renal azotemia
- renin-angiotensin-aldosterone activation
- salt and fluid retention leads to expansion of interstitial and intravascular fluid volume
What can advanced cardiac failure lead to?
Cerebral hypoxia
this is characterised by irritability, restlessness, stupor and coma
what is the aetiology of right sided heart failure?
What are the symptoms and signs due to?
Aetiology involves left heart failure & cor pulmonale
How does right sided heart failure affect the liver/spleen and pleura/pericardium?
Liver & spleen (portal congestion):
- Passive congestion (nutmeg liver)
- congestive splenomegaly
- ascites
- congestion and oedema of bowel wall
Pleura / pericardium (systemic venous congestion):
- pleural and pericardial effusions
- transudates
- oedema of peripheral and dependent parts of body
what are the 2 main categories of problems in valvular heart disease?
Problems with opening the valves - stenosis
problems with closing the valves - regurgitation
(or incompetence or “insufficiency”)
What is stenosis and what does it lead to?
What usually causes it?
It is the failure of the valve to open completely, impending forward flow
leads to pressure overload of the heart
almost always due to chronic abnormality of valvular leaflet caused by relatively few disorders
What causes regurgitation and what does it lead to?
What is it?
It is failure of the valve to close completely, allowing reverse flow
leads to volume overload of the heart
can result from intrinsic disease of the valve cusps or damage to the supporting structures
it has many causes and may appear acutely or chronically
What are the 2 different types of valvular abnormalities?
Congenital and acquired
What 2 conditions account for 70% of all valvular heart disease?
- Acquired aortic stenosis
- Acquired mitral stenosis
(rheumatic heart disease)
What is acquired aortic stenosis and what age group tends to be affected by it?
Calcification of a deformed (congenitally bicuspid) valve
tends to affect 50-70 year olds
or “senile” calcification of an anatomically normal aortic valve in the >70 age group
what is the prevalence of calcific aortic stenosis?
What is it the consequence of?
It is the most common valvular abnormality with a 2% prevalence, rising with increasing life expectancy
it is usually the consequence of age-related wear and tear of a normal valve or congenital bicuspid aortic valve3
the bicuspid aortic valve undergoes more mechanical stress so becomes stenotic earlier
What factors are involved in the pathogenesis of calcific aortic stenosis?
How is the mitral valve affected?
There is a role for hyperlipidaemia, hypertension and inflammation in pathogenesis
(factors also implicated in atherosclerosis)
mitral valve is generally normal but can be involved by extension of calcific deposits
What are the features of aortic stenosis?
- 2X gradient pressure
- left ventricular hypertrophy & ischaemia (but no hypertension)
- cardiac decompensation
- angina
- chronic heart failure
What are the survival rates like for aortic stenosis?
50% die in 5 years if angina is present
50% die in 2 years if chronic heart failure is present
What is rheumatic heart disease the result of?
What are its 3 defining features?
It follows a group A streptococcus infection, a few weeks later
it involves pancarditis
- Endocarditis
- Myocarditis
- Pericarditis