Improving care in ED



Pneumonic for secondary hypertension

R E N A L

Renal

- A.G.N

- C.R.F

- Renal artery stenosis

- Renal vasculator

- Polycystic renal disease

- Renin secreting tumours

Endocrine

- Adrenocortical - Cushings

- C.A.H.

- Dr aldosteronis

- Thyroid - overactive

- underactive

- Pituitary - A.C.T.H

- G.H.

- S.I.A.D.H.

- Pheochromacytoma

- Pregnancy

- Drugs - MAOIs

- Tyramine (foods)

- Sympathominitors

- O.C.P.

- Glucocorticoids

- Licorice

Neurogenic

- Increased I.C.P.

- Stress / pain

Arterial

- Coarctation

- Ar?????? / polyarteritis

Loading

- Increased CO

- Increased blood volume

Section 1

Cardiovascular

1) The probability of a 55 year old smoker with hypertension and hypercholesterolaemia developing coronary heart disease in the next 8 years is:

a) 5%

b) 10%

c) 25%

d) 50%

e) 75%

2) Chronic ischaemic heart disease is characterised by all of the following EXCEPT:

a) diffuse subendocardial fibrosis

b) diffuse myocardial atrophy

c) severe stenosing coronary atherosclerosis

d) diffuse, small myocardial scars

e) evolution to congestive heart failure

3) Which one of the following conditions is associated with coronary atherosclerosis?

a) stable angina only

b) unstable angina only

c) Prinzmetal’s angina only

d) stable and unstable angina

e) all of the above

4) Which one of the following conditions is MOST commonly accompanied by ST segment elevation on the ECG?

a) stable angina only

b) unstable angina only

c) Prinzmetal’s angina only

d) stable and unstable angina

e) all of the above

5) Which one of the following conditions is MOST commonly accompanied by ST segment depression?

a) stable angina only

b) unstable angina only

c) Prinzmetal’s angina only

d) stable and unstable angina

e) all of the above

6) With regard to abdominal aortic aneurysms, which is INCORRECT?

a) they have a familial tendency not solely accounted for by atherosclerosis

b) they are most frequent between the renal arteries and iliac bifurcation

c) they have a risk of rupture of 5-10% per year if >5cm diameter

d) they are rare before the age of 50 years

e) they are more common in females

7) With regard to aortic dissection, which is INCORRECT?

a) it tends to occur in 40-60 year old men

b) approximately 90% of non-traumatic cases occur in patients with antecedent hypertension

c) it is usually associated with marked dilatation of the aorta

d) it is unusual in the presence of substantial atherosclerosis

e) it is usually caused by an intimal tear within 10cm of the aortic valve

8) Which one of the following conditions frequently causes reversible injury to myocardial cells?

a) stable angina only

b) unstable angina only

c) Prinzmetal’s angina only

d) stable and unstable angina

e) all of the above

9) Using the following key, the likelihood of complications of an acute myocardial infarction, from MOST to LEAST common is:

Q - left ventricular failure

R - rupture of free wall/papillary muscle

S - thromboembolism

T - cardiogenic shock

U - arrhythmias

a) R,S,T,Q,U,

b) T,Q,U,S,R,

c) U,Q,S,T,R,

d) Q,U,T,S,R,

e) U,Q,S,R,T,

10) The pathology of unstable angina primarily involves:

a) increased blood viscosity

b) altered dynamics of myocardial blood flow

c) severe fixed atherosclerotic stenosis

d) mural thrombosis of an epicardial artery

e) mechanisms separate to the pathology of myocardial infarction

11) Which one of the following conditions is associated with a very high risk of myocardial infarction?

a) stable angina only

b) unstable angina only

c) Prinzmetal’s angina only

d) stable and unstable angina

e) all of the above

12) Regarding cardiogenic shock:

a) this is partly due to the systolic stretch phenomenon

b) depletion of ATP plays a significant role

c) the mortality associated with this condition is approximately 85%

d) it is usually indicative of a large infarct

e) all of the above are true

13) The histological appearance of contraction bands in association with acute myocardial infarction indicate:

a) previous old myocardial infarctions

b) early aneurismal formation

c) compensatory responses to decreased myocardial contractility

d) a right ventricular infarct

e) recent reperfusion therapy

14) After occlusion of a coronary artery:

a) the ischaemia is most pronounced in the epicardial region

b) loss of contractility only occurs when ultra structural changes in the myocyte are present

c) reperfusion of the ischaemic area can result in new cellular damage due to the generation of oxygen free radicals

d) Q waves on the ECG are diagnostic of transmural infarction

e) none of the above are true

15) In the typical right dominant heart, occlusion of the right coronary artery:

a) will produce a lesion in the anterior 2/3 of the interventricular septum

b) is less common than occlusion of the left circumflex artery

c) will not affect the interventricular septum

d) will produce a lesion in the anterior wall of the left ventricular

e) none of the above are true

16) Which of the following is the LEAST common cause of aneurysm formation?

a) cervical rib

b) ankylosing spondylitis

c) atheroma

d) coronary angioplasty

e) syphilis

17) The MOST common site of cerebral aneurysm is:

a) middle meningeal artery

b) middle cerebral artery

c) anterior cerebral artery

d) anterior meningeal artery

e) posterior cerebral artery

18) Which of the following statements about aneurysm is INCORRECT?

a) they rupture at the apex rather than at the sides

b) traumatic aneurysms most commonly involve lower limb arteries

c) they more commonly leak when the diameter is greater than 5cm

d) atheromatous aneurysms most commonly involve the aorta

e) they may be infective in origin

19) Which of the following vessels is LEAST susceptible to aneurismal dilation?

a) innominate artery

b) subclavian artery

c) ascending thoracic aorta

d) brachial artery

e) carotid artery

20) Pathologic features or aortic dissection include all of the following EXCEPT:

a) elastic fragmentation

b) inflammatory cell infiltrate

c) cystic medial necrosis

d) focal medial fibrosis

e) intimal tear

21) Which of the following patterns of arterial blood supply is INCORRECT?

a) the brain has a parallel arterial system

b) the kidney has end-arteries

c) the liver has a double blood supply

d) the forearm has a parallel arterial system

e) the jejunum has end-arteries

22) Which of the following is NOT commonly associated with berry aneurysms?

a) pre-existing cerebral arteriovenous malformation

b) rupture when diameter exceeds 10mm

c) smooth muscle discontinuity in media

d) polycystic ovary disease

e) absence at birth

23) Which of the following vessels is LEAST susceptible to atheromatous plaque formation?

a) superior mesenteric artery

b) popliteal artery

c) Circle of Willis

d) descending thoracic aorta

e) internal carotid artery

24) Causes of cardiogenic shock include all of the following EXCEPT:

a) myocardial damage

b) tamponade

c) excessive blood loss

d) arrhythmias

e) outflow obstruction

25) “Caisson” disease refers to:

a) systemic emboli

b) pulmonary emboli

c) amniotic fluid emboli

d) air emboli

e) fat emboli

26) In acute myocardial infarction, which change will occur in the time frame indicated:

a) ATP reduced to 50% of normal - 25 minutes

b) microvascular injury - after 3-4 hours

c) onset of irreversible cell injury - 10 minutes

d) ATP reduced to 10% of normal - 60 minutes

e) loss of contractility - 1-2 minutes

27) Acute myocardial infarction:

a) is isolated to the right ventricle in < 5% of cases

b) involves the atria in 1-2% of cases

c) is due to left anterior descending artery critical blockage in 70% of cases

d) is due to right main artery critical blockage in 10% of cases

e) is due to critical blockage of left circumflex artery in 35% of cases

28) 1-2 hours following acute myocardial infarction, the change occurring in myocardium is:

a) ultra structural cellular features of irreversible damage

b) the appearance of “wavy” fibres

c) staining defects in preparations with tetrazolium dye

d) the appearance of classical features of coagulative necrosis

e) none of the above

29) The MOST frequent complication of acute myocardial infarction is:

a) cardiogenic shock

b) thromboembolism

c) congestive cardiac failure

d) arrhythmia

e) deep venous thrombosis

30) Of the following complications of acute myocardial infarction, the MOST frequently occurring is:

a) ventricular rupture

b) sudden death

c) pulmonary oedema

d) cardiogenic shock

e) thromboembolism

31) Subendocardial myocardial infarction:

a) is reliably predicted by the absence of Q waves on the ECG

b) is usually associated with diffuse coronary atherosclerosis

c) is associated with plaque rupture without thrombosis

d) is associated with vessel thrombosis, but not plaque rupture

e) is usually associated with plaque rupture and overlying thrombosis

32) Sudden cardiac death:

a) is most frequently due to ventricular wall rupture

b) is most frequently due to aortic stenosis

c) is often the first clinical manifestation of ischaemic heart disease

d) is rarely associated with single vessel critical coronary artery stenosis

e) is associated with acute myocardial infarction in 90% of cases

33) Which is the MOST frequent cardiac valve abnormality?

a) mitral stenosis

b) mitral incompetence

c) aortic incompetence

d) aortic stenosis

e) pulmonary incompetence

34) A patient presents unwell, four weeks after having a streptococcal pharyngitis. Which of the following would confirm a diagnosis of rheumatic fever?

a) fevers and pan systolic apical murmur

b) fevers and a raised ASO titre

c) migratory polyarthritis and subcutaneous nodules

d) fever and raised ESR

e) a raised ASO titre, pan systolic murmur and migratory polyarthritis

35) Abdominal aortic aneurysms:

a) usually involve the renal arteries

b) usually involve the iliac arteries

c) are more common in post menopausal women than men of the same age group

d) are familial

e) if 4-5 cm in diameter, have an annual risk of rupture of approximately 10-15%

36) A 65 year old man presents with left-sided chest pain and ECG features consistent with pericarditis. Which is the MOST likely cause of this condition?

a) systemic lupus erythematosis

b) renal failure

c) trauma

d) post myocardial infarction

e) bacterial infection

37) The MOST common cause of pericarditis is:

a) SLE

b) drug hypersensitivity

c) trauma

d) post myocardial infarction

e) bacteria

38) The MOST common pathogens of infective endocarditis are:

a) staphylococcal

b) enterobacteriaceae

c) streptococcal

d) chlamydial

e) fungal

39) All of the following are features of rheumatic fever EXCEPT:

a) carditis

b) subcutaneous nodules

c) erythema nodosum

d) elevated antistreptolysin

e) Aschoff bodies in the heart

40) Abdominal aortic aneurysms:

a) do not develop before the age of 50

b) are not familial

c) are most common in women

d) with a diameter ≤ 4cm have a risk of rupture of 2% per year

e) with a diameter ≥ 5cm have a risk of rupture of 30% per year

41) In ischaemic heart disease:

a) acute myocardial infarction has a circadian peak in the mid to late afternoon

b) 30% of myocardial infarcts are “silent”

c) an eccentric atherosclerotic plaque is more likely to rupture than a circumferential one

d) atherosclerotic plaque rupture with overlying thrombosis will progress to infarction if left untreated

e) an atherosclerotic plaque causing 60% stenosis will be unlikely to cause infarction if it ruptures and becomes complicated

42) The vessel most intensely involved by atherosclerotic plaques is:

a) abdominal aorta

b) coronary artery

c) internal carotid artery

d) popliteal artery

e) middle cerebral artery

43) Which of the following is the LEAST significant risk factor for atherosclerosis?

a) obesity

b) hypercholesterolaemia

c) hypertension

d) diabetes

e) cigarette smoking

44) A major risk factor that predisposes towards atherosclerosis is:

a) male gender

b) diabetes

c) obesity

d) family history of premature atherosclerosis

e) physical inactivity

45) Atheroma predominantly effects:

a) the intima

b) the media

c) the adventitia

d) the media and adventitia

e) the whole arterial wall

46) The foam cells in atherosclerotic lesions are:

a) intimal cells full of lipid

b) monocytes full of lipid

c) smooth muscle cells that have migrated from the media to the intima

d) platelets that are adherent to the plaque

47) Which is NOT a feature of atheromatous plaques?

a) it mainly involves the muscular and elastic arteries

b) lesions tend to be covered with a fibrous cap of smooth muscle cells

c) the edges (“shoulder”) contain macrophages and T-cells

d) the core is a necrotic mass of cholesterol and other lipids with foam cells

e) it mainly occurs within the tunica media

48) After the abdominal aorta, in general, which site is the most heavily effected by atheroma?

a) descending thoracic aorta

b) coronary arteries

c) popliteal artery

d) internal carotid artery

e) vessels of the Circle of Willis

49) The hyperlipidaemic contribution to the pathogenesis of atheroma is thought to occur via:

a) atheroma macrophages uptaking lipid via LDL receptors

b) hyperviscosity secondary to hyperlipidaemia

c) oxidation of lipids within the atheroma

d) the thrombogenic nature of lipids

e) apolipoprotein B-48

50) Regarding haemorrhagic infarction of the brain, which of the following is NOT true?

a) it usually results from an embolic event

b) it usually contains multiple petechial haemorrhages which may be confluent

c) the distinction between this and non haemorrhagic infarcts is clinically insignificant

d) the haemorrhages are presumed to be secondary to reperfusion injury

e) the size of it will depend in part upon the collateral blood supply to that area

51) The most common site of origin of emboli causing cerebrovascular disease is:

a) common carotid artery

b) internal carotid artery

c) the heart

d) either end of basilar artery

e) intra-cranial vessels

Section 1

Cardiovascular – Answers

1. C

2. A

3. E

4. C

5. D

6. E

7. C

8. E

9. C

10. D

11. B

12. E

13. E

14. C

15. E

16. E

17. C

18. A

19. D

20. B

21. E

22. D

23. A

24. C

25. D

26. E

27. A

28. B

29. D

30. C

31. B

32. C

33. D

34. C

35. D

36. D

37. D

38. C

39. C

40. D

41. C

42. A

43. A

44. B

45. A

46. B

47. E

48. B

49. C

50. C

51. C

Section 2

1) Which is NOT a compensatory change in congestive heart failure?

a) myofibre hypertrophy

b) myofibre stretch

c) bradycardia

d) blood volume expansion

e) ventricular dilatation

2) Which is NOT a cause of pure right sided heart failure?

a) tricuspid valvular disease

b) pulmonary embolus

c) COAD

d) hypertension

e) myocarditis

3) Which is a major (Jones) criteria for rheumatic fever?

a) erythema nodosum

b) fever

c) past history of rheumatic fever

d) raised ESR

e) polyarthritis

4) Which endothelial product is prothrombotic?

a) prostacyclin

b) thrombomodulin

c) plasminogen activator

d) heparin-like molecules

e) tissue-factor

5) Blockage of the left circumflex artery will cause infarction in:

a) anterior left ventricle

b) posterior septum

c) lateral left ventricle

d) apex

e) right ventricle

6) Morphological changes in an acute myocardial infarction include:

a) coagulative necrosis within 1 hour

b) ATP 10% of normal within 10 minutes

c) yellow soft demarcated area within 3-10 days

d) new blood vessel formation at 3 days

e) loss of contractility within 5 minutes

7) What organism most commonly causes SBE?

a) staphylococcus aureus

b) staphylococcus epidermidis

c) group A streptococcus

d) α haemolytic streptococcus

e) haemophilus

8) Regarding aortic dissection:

a) there is a blood-filled channel along the laminar planes of the intima

b) hypertension is present in 75% of cases

c) is mostly in 40-60 year old women

d) there is marked dilatation of the aorta

e) is unusual in severe atherosclerosis

9) Which is a major risk factor for atherosclerosis?

a) obesity

b) physical inactivity

c) stress (type A personality)

d) hypertension

e) homocysteine

10) Which vessel is least likely to develop atherosclerosis?

a) mesenteric artery

b) Circle of Willis

c) descending thoracic aorta

d) internal carotid artery

e) popliteal artery

11) Bicuspid aortic valve – which is FALSE?

a) incidence is 1-2%

b) no increased predisposition to aortic stenosis

c) increased association of coarctation and dissection

d) increased risk of infective endocarditis

e) increased risk of valve incompetence

12) Major Jones criteria for rheumatic fever include:

a) fever

b) previous rheumatic fever

c) ESR > 20

d) prolonged PR interval on ECG

e) polyarthritis

13) Hypertension is a risk factor for all EXCEPT:

a) renal failure

b) heart failure

c) ischaemic heart disease

d) aortic stenosis

e) cerebrovascular accident

14) Aortic dissection:

a) most common in 40-60 year old females

b) are most frequently associated with aneurysms

c) extend along the intimal plane of the aorta

d) usually occur 2cm from the aortic valve

e) type A involves the great vessels of aortic arch

15) An anticoagulant produced by endothelium is:

a) thrombomodulin

b) factor III (vWF)

c) plasminogen activator inhibitor

d) endothelin

e) interleukin-6

16) Endothelial cells:

a) have many pinocytic vesicles

b) form junctional complexes

c) contain Weibel-Palade bodies

d) elaborate von Willebrand factor

e) have all of the above characteristics

17) The cardothelium does not:

a) serve as a semi-permeable membrane

b) migrate to the media in response to injury

c) regulate thrombosis, thrombolysis and platelet adherence

d) regulate leukocyte interactions with vessel wall

e) metabolise hormones

18) The endothelium does not:

a) have many synthetic properties

b) have many metabolic properties

c) maintain the non-thrombogenic blood tissue interface

d) constrict to reduce flow in response to drugs or hormones

e) modify lipoproteins in the arterial wall

19) Endothelial cells are not activated by:

a) cytokines

b) high PCO2

c) bacterial products

d) hypoxia

e) haemodynamic forces

20) Endothelial cells do not elaborate:

a) prostacyclin and NO/EDRF

b) plasmin

c) heparin-like molecules

d) endothelin and ACE

e) extracellular matrix

21) Which of the following forms of vasculitis does not involve glomeruli?

a) Henoch Schoenlein purpura

b) Wegeners granulomatosus

c) polyarthritis nodosa

d) Goodpastures

e) SLE

22) Which of the following vasculilides is associated with a raised pANCA?

a) rocky mountain spotted fever

b) drug induced

c) rheumatoid

d) cryoglobulinaemia

e) Churg Strauss

23) In which of the following groups of vasculitis is the pathogenesis well defined?

a) Takayasu pulseless disease

b) microscopic polyangiitis

c) polyarthritis nodosa

d) giant cell arteritis

e) Buergers disease (thrombophlebitis obliterans)

24) In valvular disease:

a) in nonbacterial thrombotic endocarditis, small sterile vegetations are present on either or both sides of the valve leaflets

b) group A β–haemolytic streptococci is the most common causative agent of infective endocarditis

c) 12% of the population have congenitally bicuspid aortic valves

d) mitral regurgitation is the most frequent of all valvular abnormalities

e) ankylosing spondylitis is a cause of aortic regurgitation

25) In myocardial disease:

a) in hypertrophic cardiomyopathy, the free wall of the left ventricle is disproportionately thickest

b) dilated cardiomyopathy has a familial occurrence in 20-30% of cases

c) EBV is a common cause of viral myocarditis

d) giant cell myocarditis has a relatively good prognosis

e) in haemochromatosis, iron deposition is preferentially in the conduction system

26) In myocardial infarction:

a) white people are twice as likely to suffer a myocardial infarction compared with black people

b) irreversible cell injury occurs after one hour of ischaemia

c) the right coronary artery supplies the ventricular septum

d) coagulative necrosis begins within 24 hours of a myocardial infarction

e) myocardial infarctions are silent in 5% of cases

27) Regarding atherosclerosis:

a) fatty streaks cause disturbance in blood flow

b) fatty streaks appear in aortas of all children older than one year

c) atheromatous plaques are composed of a luminal surface of foam cells

d) coronary artery lesions are often mainly fatty atheromas

e) the lipid in a plaque is primarily triglyceride

28) After the abdominal aorta, the next most affected vessel with atherosclerosis is:

a) Circle of Willis

b) thoracic aorta

c) axillary artery

d) popliteal artery

e) internal carotid artery

29) Major modifiable risk factors for atherosclerosis include:

a) age

b) type A personality

c) increased plasmo homocysteine

d) diabetes mellitus

e) physical inactivity

30) Regarding cellular depletion of ATP in myocardial infarction:

a) 10% at 10 minutes

b) 50% at 20 minutes

c) there is no ATP in myocytes

d) 10% at 40 minutes

e) 50% leading to irreversible injury

Section 2

Answers

1. C

2. D

3. E

4. E

5. C

6. C

7. D

8. E

9. D

10. A

11. B

12. E

13. C

14. E

15. A

16. E

17. B

18. D

19. B

20. B

21. no answer

22. no answer

23. no answer

24. no answer

25. no answer

26. no answer

27. no answer

28. no answer

29. no answer

30. no answer

Section 3

1) Which of the following is not a primary cause of diastolic dysfunction?

a) massive left ventricular hypertrophy

b) myocardial fibrosis

c) aortic regurgitation

d) deposition of amyloid

e) constrictive pericarditis

2) At autopsy, the heart of patients having CHF is characterised by all of the following EXCEPT:

a) increased weight

b) increased capillary density

c) progressive wall thinning

d) chamber dilatation

e) microscopic changes of hypertrophy

3) Left-sided heart failure is most often caused by the following, EXCEPT:

a) ischaemic heart disease

b) hypertension

c) aortic and mitral valvular disease

d) myocardial diseases

e) pulmonary diseases

4) The most common cause of IHD syndrome is:

a) stenosing coronary atherosclerosis

b) intraluminal thrombosis

c) rupture or fissure of an atherosclerotic plaque

d) platelet aggregation

e) coronary vasospasm

5) Compensatory vasodilation is not sufficient to meet increased myocardial demand, beyond an obstruction of a major coronary artery by:

a) 45%

b) 55%

c) 65%

d) 75%

e) 85%

6) Which of the following is not thought to be associated with acute rupture of an atherosclerotic plaque?

a) vasospasm

b) tachycardia

c) circadian periodicity

d) intraplaque haemorrhage

e) raised intrathoracic pressure

7) Which of the following is associated with ST segment elevation on the ECG?

a) stable angina

b) Prinzmetal’s angina

c) Unstable angina

d) All of the above

e) None of the above

8) Which of the following is incorrect regarding Q wave infarcts?

a) acute mortality in non-Q wave infarcts is half that in patients with Q wave infarcts

b) non-Q wave infarcts have a low early mortality rate

c) non-Q wave infarcts have a high late mortality rate

d) the presence or absence of Q waves reliably predicts the distinction between subendocardial and transmural infarcts

e) none of the above

9) What proportion of myocardial infarcts occur in people under the age of 65:

a) 65%

b) 55%

c) 45%

d) 35%

e) 25%

10) In the typical right dominant heart, occlusion of the LAD coronary artery will produce an infarct in the:

a) anterior two thirds of the interventricular septum

b) lateral wall of the left ventricle

c) posterior one third of the interventricular septum

d) inferior wall of the left ventricle

e) posterior wall of the left ventricle

11) Which is the least common complication of acute myocardial infarction?

a) cardiac arrhythmia

b) left ventricular failure

c) cardiogenic shock

d) rupture of free wall, septum or papillary muscle

e) thromboembolism

Section 3

Answers

1. no answer

2. …..

3. ….

4. ….

5. ….

6. ….

7. ….

8. ….

9. ….

10. ….

11. …..

Ischaemic Heart Disease

Definition:

Group of four syndromes which result in myocardial ischaemia.

Imbalance between perfusion of myocardium and its demand for oxygenated blood.

Results in deficiency of oxygen and nutrient substances and reduced clearance of metabolites.

Four Syndromes:

1. Myocardial infarction

2. Angina pectoris – three types: Stable

Prinzmetal

Unstable

3. Chronic ischaemic heart disease with heart failure

4. Sudden cardiac death (fatal arrhythmia)

Risk

Unmodifiable: gender, family history, age, genetic predisposition,

Major: smoking, diabetes mellitus, HT, hypercholesterolaemia

Minor: exercise, obesity, ETOH, increased CHO diet, increased homocysteine, stress (type A personality), post menopause, lipoprotein

Pathogenesis:

1 Atherosclerosis → know definition atherosclerosis

Disease of intima of muscular and elastic arteries characterised by atheromatosis plaques in intima which project into lumen of vessel

← Atherosclerosis can cause fixed coronary obstructions.

← >90% people with IDH have coronary atherosclerosis which decreases the radius and compromises the flow.

← Most have ≥ 1 lesion which decreases cross sectional area of vessel lumen by ≥ 75%.

← Lesions usually in first few centimetres of artery

2. Role of acute changes in atherosclerotic plaque

3. Role of coronary thrombosis

4. Role of vasoconstriction

* 2, 3 and 4 cause sudden change in coronary vessel potency and blood flow to myocardium

Acute changes in plaque

➢ Haemorrhage into plaque (sudden increased volume)

➢ Rupture / fissuring of plaque

➢ Erosion / ulceration overlying endothelium + thrombosis

Thrombosis

pH adhesion, activation, aggregation (exposed plaque contents and endothelial BM)

+ mediators of coagulation leads to fibrin clot

consequences of thrombosis (decreased lumen/occlude lumen)

➢ Occlusive leads to transmural AMI

➢ Non-occlusive leads to unstable angina, subendocardial AMI, sudden cardiac death

➢ Embolise downstream

➢ + smooth muscle contraction

➢ + TxA2 and pH constituents which further + thrombosis

➢ nb lipoprotein a (on LDL) can – fibronolysis

Vasoconstriction

SM + by: Circulating adrenergic agonists

Locally released pH contents

Inflammation mediators

Decreased secretion NO by damaged endothelium

Consequences of vasoconstriction

➢ Decreased vessel lumen

➢ Altered forces in vessel – increased risk plaque rupture

Myocardium is O2 dependent tissue

Coronary perfusion / O2 delivery

(???? Are the “+” an abbreviation of increased???? “-“ perhaps negate or similar)

Ischaemic Heart Disease

Myocardial ischaemia = imbalance between supply (perfusion) and demand (for O2)

→ insufficiency of O2

→ reduced availability of nutrients

→ inadequate removal of waste products

Mostly (>90%) due to decreased coronary blood flow secondary to atherosclerosis

Pathogenesis

1. Fixed coronary obstruction

2. Acute plaque change

3. Coronary thrombosis

4. Vasoconstriction

Angina

Characterised by paroxysmal and recurrent attacks of precordial chest pain

1. stable angina

2. Prinzmetal variant angina

3. Unstable angina

Myocardial Infarction

Death of heart muscle

Leading cause of death in industrialised countries

Types

1. transmural – full thickness, single a. territory

2. subendocardial – inner 1/3 to ½ , extends beyond a. territory

Risk Factors

As for atherosclerosis:

1. major, non-modifiable (age, male, genetic)

2. major, modifiable (lipids, HT, cigs, DM)

3. other (obesity, inactivity, stress, homocysteine, etc)

Pathogenesis

1. atherosclerotic plaque change

2. platelet adhesion, aggregation, activation

3. other mediators + (2) → extrinsic coagulation

4. occlusive thrombus

→ cell death throughout anatomic region supplied by a.

outcome depends on severity and duration of occlusion

Location

1. LAD (40-50%) → ant. LV, ant. Septum, apex

2. RCA (30-40%) → inf-post. LV and RV, post. septum

3. LCX (15-20%) → lat. LV

Morphology

|Cellular: |Seconds : onset of ATP depletion |

| |< 2 min : loss of contractility |

| |10 min : ATP 50% of normal |

| |40 min : ATP 10% of normal (irreversible cell injury) |

| |> 1 hour : microvascular injury |

|Time |Light microscopy |Gross features |

|0-4 hours |subcellular change (EM) | |

|4 hours – 3 days |coagulative necrosis, haemorrhage, oedema |dark mottling |

|1-7 days |neutrophils | |

|3-10 days |macrophages → phagocytosis, granulation |yellow-tan & soft |

|7-14 days |granulation tissue, new blood vessels |red-grey borders |

|2-8 weeks |increased collagen, decreased cells |grey-white scar |

Reperfusion

Before 20 minutes → may prevent all necrosis

After 20 minutes → can salvage some cells

Critically damaged myocytes die quicker (contraction band necrosis, ?↑Ca2+)

Small amount of new cellular damage (?O2 free radicals)

“stunned myocardium” = prolonged (3d) post ischaemic ventricular dysfunction

“hibernating myocardium” = chronically depressed function

Complications

Around 75% of MI patients suffer complications

Depend on MI size, site and transmural extent

1. contractile dysfunction → LVF, cardiogenic shock

2. arrhythmias (s. brady, PVCs, VT/VF, asystole, heart block (inf MI))

3. myocardial rupture

4. pericarditis

5. RV infarction

6. infarct extension/expansion

7. mural thrombus → embolism

8. ventricular aneurysm

9. papillary muscle dysfunction → MR

10. progressive late CCF

Chronic IHD

Progressive heart failure as a result of ischaemic myocardial damage

Sudden Cardiac Death

Unexpected death from cardiac causes

Causes: IHD

Other – congenital, valvular disease, cardiomyopathy, conduction, abnormalities

Ultimate cause nearly always VF or asystole

-----------------------

Normal coronary a. fixed obstruction

(typical angina)

plaque disruption severe fixed obstruction

(chronic IHD)

variable obstruction occlusive thrombus

(USAP, subendo. MI) (transmural MI)

sudden death

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