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Flashcards in Cardiovascular diseases Deck (35):

What is ischaemic heart disease?

Inadequate blood supply to the myocardium


What are the main causes of ischaemic heart disease?

- Atherosclerosis and/or thrombus*
- Myocardium hypertrophy due to systemic hypertension
- any imbalance in supply vs demand


At what % occlusion does auto regulation of the coronary arteries breaks down?

75% occlusion


At what % occlusion does auto regulation of coronary arteries break down at rest?

90% occlusion


What happens with acute cardiac ischaemia?

Myocyte dysfunction/death due to blood flow and loss of aerobic metabolism


What is the length of time where damage is reversible with ischaemia?

20-30 mins


At what point in the cardiac cycle doe cardiac perfusion occur?



What are the 3 types off angina pectoris?

Stable/typical - fixed dysfunction and predictable symptoms

Variant/prinxmetal - coronary artery spasm - effects less predictable

Crescendo/unstable - red flag - usually due to plaque disruption - worsening symptoms, unpredictable (MI risk = high)


What two syndromes come under acute coronary syndrome?

MI - irreversible damage of myocytes

Crescendo/unstable angina (similar - treated in same way)


There are two types of MI - what are they?

Subendocardial - non full thickness** (most vulnerable region - poorly perfused)

Transmural - regional (kills entire wall)


What is the main characteristic of subendocarial infarction?

Doesn't need acute coronary occlusion to occur MISMATCH BETWEEN DEMAND AND SUPPLY

- because it is normally poorly perfused, can occur with stable atherosclerotic occlusion of coronary circulation and following a hypotensive episode


What are subendocardial MIs also referred to as?

Non-ST elevation MI


Why are transmural MIs so debilitating?

Death of large region (entire wall) - results in necrosis, fibrosis and formation of fibrous (collagen) scar - cannot pump properly (loss of specialised tissue)


Name the 5 stages of MI morphology (24hrs -6 weeks)

24hrs - normal

1-2 days - pale, oedema with myocyte necrosis and neutrophils

3-4 days - yellow with haemorrhagic edge, myocyte necrosis with macrophage invasion

1-2 weeks - pale, thin (red/grey) - granulation tissue then fibrosis

3-6 weeks - fibrotic scar formation (collagen) (can't tell how old it is after 4 weeks)


What are the 2 main markers of cardiac damage?

TROPONIN T and I (detectable after 2-3 hrs, peaks at 12, detectable for 1 week)

CREATINE KINASE MB - detectable 2-3h, peaks 10-24 hrs, detectable for 3 days

Also myoglobin (peaks 2hrs) but non-specific - skeletal muscle too


What are the 3 subtypes of creatine kinase

CK MM - skeletal muscle and cardiac
CK BB - brain and lung
CK MB - mainly cardiac but also skeletal


Name some of the complications of MI

-Contractile dysfunction and chronic heart failure

-VF, arrhythmias, sudden cardiac death

- Myocardial rupture

- Ventricular aneurysm

- Mural thrombus - stroke!

- Autoimmune pericarditis (Dressler's syndrome) (3 day mark - neutrophil inflammatory response)


What is chronic ischaemic heart disease characterised by?

Hypertrophy and dilatation


What can chronic IHD cause?

Sudden death/MI/angina pectoralis on exertion


what is hypercholestroaemia and what are the most common types?

Mutations of genes involved in cholesterol metabolism

LDL receptor (1 in 500)
Apolipoprotein B (1 in 1000)


What do individuals with heterozygotic hypercholesterolaemia develop?

- cholesterol deposit (foam cells to endothelium - atherosclerosis)

- tendon, perioccular, corneus arcus, early atherosclerosis



What are considered abnormal diastolic and systolic BPs?

Diastolic = above 90 mmHg
Systemic = above 140 mmHg


What is the effect of hypertension on the heart?

LV hypertrophy without dilatation (initially then subsequent dilatation when it fails to pump blood sufficiently - final stage)


What is the main effect of hypertension on the renal system?

Slow deterioration of renal function - chronic renal failure (damage to vessels - arterial intimal fibroelastosis)

Kidneys have stippled appearance


What can hypertension cause in the brain? (hypertensive cerebrovascular disease)

Berry aneurysm
Intracerebral haemorrhage


What is acute hypertensive crisis and what does it cause?

Rapid increase in BP above 180/120 mmHg

Causes organ failure - hypertensive encephalopathy (brain - confusion, vomiting, convulsions, coma/death), renal failure and retinal haemorrhage


What is pulmonary hypertension and what is it caused by?

- Increased pressure in pulmonary vasculature

Caused by loss of pulmonary vasculature

- chronic obstructive lung disease
- pul thrombi/emboli
- reduced alveoli vent
- Interstitial lung disease


What does pulmonary hypertension cause?

- Increased pulmonary resistance (OEDEMA)
- Increase RV work to pump blood
- RV hypertrophy and later dilatation as RV failure occurs


Name some causes of secondary hypertension

Renal - acute glomerulonephritis, chronic renal disease, polycystic kidneys

Endocrine - Cushing syndrome, primary aldosteronism, congenital adrenal hyperplasia, hyperthyroidism

CV - coarticulation of aorta


Describe RAAS

- Angiotensinogen converted to Angiotensin I by renin (produced in juxtaloglomerular apparatus in kidney)

- angiotensin I converted to angiotensin II (lungs many - why ACE inhibitors cause chronic cough) - potent vasoconstrictor

- angiotensin II also stimulate adrenal cortex release of aldosterone (Na and H2O retention - increased circulating volume and increased BP)


What is CONNS syndrome and how is it caused?

Excess aldosterone secretion from adrenal cortex

Usually adrenocortical carcinoma/adenoma


How is CONNS syndrome characterised and what does it cause?

high aldosterone with low renin

High BP (Na and H2O retention)

K loss - metabolic alkalosis, muscle weakness, arrhythmia


What is pheochromocytoma and what does it cause?

Tumour of the adrenal medulla

Excessive synthesis and secretion of catecholamines - increase adrenaline/NA - increases vasoconstriction and BP


What is cushing's disease and what is it mostly caused by?

Overproduction of CORTISOL from adrenal cortex

Caused by pituitary adenoma (80%), adrenocortical adenoma or paraneoplastic effect of other neoplasms


What does Cushings disease cause?

Hypertensive effect - cortisol has metabolic effects - increases sympathetic NS active

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