Cardiology Flashcards
Time intervals in MI
Onset of ATP depletion - seconds
Loss of contractility <2mins
ATP reduced 50% in 10 mins
ATP reduced 10% in 40 mins
Irreversible cell injury 20-40 mins
Microvascular injury >1 hour
Histological change seen with MI within 24 hours
Pallor and oedema and coagulation necrosis
Histolological changes seen within 12-72 hours
Neutrophilic infiltration into necrotic tissue
Ongoing coagulation necrosis
Microscopic changes seen in MI in 3-7 days
Dead myocytes disintegrate, resorption by macrophages and enzyme proteolysis
Disintegration of myofibres
Microscopic changes seen in MI in 7-10 days
Granulation tissue replaces necrotic tissue - development of dense fibrous scar
Microscopic changes after MI in 2-8 weeks
Collagen deposition
In congestive failure what is the compensatory change of the myocardium
Hyper trophy
In congestive heart failure what changes occur in pressure loaded cardiac hyper trophy
Diffuse fibrosis
Decrease in myocyte ratio
Increase in mutations of sarcomeres
Synthesis of abnormal proteins
Amyloid deposition
What is the most common cause of fungal endocarditis
Candida albicans ( causing over half)
What causes endocarditis in a native but damaged/ abnormal valve
Most commonly S Viridins 50-60%
In endocarditis what is the more virulent cause that can infect healthy and deformed valves
S.Aureus
What is the most common organism for endocarditis in IVDU
S.Aureus
What is the most common causative organism of endocarditis in prosthetic valves
S. Epidermidis
What is a key microscopic feature of rheumatic fever
Aschoff bodies
In rheumatic fever what are aschoff bodies
Scattered inflammatory lesions
Foci of swollen collagen surrounded by lymphocytic T cells
Can be found in any of the 3 heart layers - pancarditis
What are the most common types of pericarditis
Fibrinous and serofibrinous pericarditis
Consisting of serous fluid mixed with fibrinous exudate
Causes of fibrinous and serofibrinous pericarditis
Post MI Dressler’s syndrome
Uraemia
Radiation
RA SLE
What are the 5 types of acute pericarditis
- Serous pericarditis - serous inflammatory exudate often of unknown cause
- Fibrinous and serofibrinous - most common
- Purulent (suppurative) - invasion of pericardial space by infective organisms
- Haemorrhagic - following surgery or tuberculosis or malignancy
- Caseous - caused by tuberculosis
What are the 2 types of chronic pericarditis
Adhesive mediostinopericarditis - often after tuberculous or purulent pericarditis
Constrictive pericarditis - thick fibrous obliteration of pericardial sac often with calcification, after tuberculous
In CCF what causes blood volume expansion
Increased aldosterone
Causes sodium and water retention
What are the 5 things in the major Jones criteria for rheumatic fever
- Erythema marginatum of the skin
Skin lesions with erythematous rims and central clearing in a bathing suit distribution - Sydenham chorea - Neuro disorder, rapid involuntary movements
- Pancarditis
- Subcutaneous nodules - usually across joints and tendons
- Migratory large joint polyarthritis
What is in the minor Jones criteria for rheumatic fever
Fever
Arthralgia
Leukocytosis
First degree heart block
Previous rheumatic fever
What and where are baroreceptors
Stretch receptors
In the wall of the heart and blood vessels - tunica adventitia
When do baroreceptors discharge at a greater rate
When the pressure rises in the structures they are in
