Cardiovascular Diseases 1 Flashcards
Inadequate blood supply to the myocardium
Ischaemic heart disease
What degree of coronary artery stenosis is insufficient at rest?
> 90%
At what stage in the heart cycle does most perfusion occur?
During diastole
3 types of angina pectoris
Stable/typical
Variant/prinzmetal
Crescendo/unstable
What type of angina is a fixed obstruction, predictable and related to exertion
Stable
What type of angina is due to a coronary artery spasm?
Varient/prinzmetal
What type of angina is often due to plaque disruption?
Crescendo/unstable
3 causes of acute coronary syndrome?
Acute MI with ST elevation
Acute MI without ST elevation
Unstable/crescendo angina
Give 2 types of MI, based on what area of the heart is affected
Subendocardial
Transmural
Is subendocardial MI associated with ST elevation?
No
Causes of subendocardial MI
Stable atheromatous occlusion
Acute hypotensive episode
What type of MI is caused by a sudden blockage that kills the whole wall?
Transmural
How do transmural MIs heal?
By scarring and fibrosis- no regeneration of myocytes and no contractile function
Causes of transmural MIs
Coronary atheroma and thrombus
Gross appearance of heart tissue
Normal/dark
Gross appearance of heart tissue 1-2 days after an MI
Yellow, infarct centre
Gross appearance of heart tissue 3-7 days after an MI
Hyperaemic border, yellow centre
Gross appearance of heart tissue
Red/grey
Gross appearance of heart tissue 3-6 weeks after an MI
Scar
Microscopic appearance of heart tissue
Necrosis and neutrophils
Microscopic appearance of heart tissue 1-2 days after an MI
More necrosis and neutrophils
Microscopic appearance of heart tissue 3-7 days after an MI
Macrophages
Microscopic appearance of heart tissue 1-3 weeks after an MI
Granulation tissue
Microscopic appearance of heart tissue 3-6 weeks after an MI
Collagen scar
At what point after an MI is the heart tissue the weakest?
3-7 days- infiltrated with macrophages
Name 3 blood markers of cardiac myocyte damage
Troponins T&I
Creatinine Kinase
Myoglobin
Name the blood markers of cardiac myocyte damage in order of their appearance in the blood post MI
Myoglobin, CKMB, Troponin
When do troponin levels peak post MI?
12 hours
When else can troponin levels be high in the blood, other than post MI?
Renal failure
PE
Heart failure
Myocarditis
How does troponin prevent muscle contraction?
binds to actin and stops in binding to tropomyosin
What are the 3 sybtypes of creatinine kinase and which tissues are they found in?
CKMM-cardiac and skeletal muscle
CKBB-brain, lung
CKMB-mainly cardiac, also skeletal muscle
7 complications of MIs
Contractile dysfunction and chronic cardiac failure infarct extension pericarditis arrhythmias mural thrombus ventricular aneurysm myocardial rupture
In familial hypercholesterolaemia, what are the specific genes affected?
low density lipoprotein receptor gene
apolipoprotein B
What is the result when the LDL receptor gene is not functional?
LDLs are not taken in by the liver, so instead they are taken in by scavengers and settle underneath endothelial cells- contribute to atheroscerosis
What is the difference between primary and secondary hypertension
primary hypertension develops over a long period of time due to obestiy, diabetes etc. Secondary hypertension develops much more rapidly and is the result of a condition or disease within the body e.g. renal complications, endocrime
Which is more common, primary or secondary hypertension?
Primary (accounts for 95%)
Too much sodium in the blood results in an increase in intravascular volume. As the perfusion exceeds metabolic demand, the body responds by vasoconstriction, resulting in a steady state haemodynamic pattern. Describe this pattern
Increase in blood pressure
Increase in systemic vascular resistance
Normal cardiac output
What are the 3 main organs affected by hypertension?
Kidneys, heart and brain
Describe the pathogenesis of hypertensive heart disease
Sytemic hypertension, Increase in LV blood pressure, LV hypertrophy without dilation initially in response to an increase in work load. Long term-dilation of LV.
What is a normal LV thickness?
18mm
What BP categorises as a bypertensive crisis?
> 180/120 mmHg
Dramatic, immediate complications requiring urgent treatment. Results from primary or secondary hypertension
Hypertensive crisis
What are the 3 main effects of a hypertensive crisis
Acute hypertensive encephalopathy
Renal failure
Retinal haemorrhages
Diffuse cerebral dysfunction; confusion, vomiting, convulsions, coma and death
Acute hypertensive encephalopathy
3 causes of pulmonary hypertension
COPD
Fibrosis (interstitial lung diseases)
Emboli or thrombosis
Pulmonary hypertension occurs secondary to what
LV failure
Longitudinal study to identify cardiovascular risk factors- calculates an individual risk
Framingham heart study
Where is renin synthesises, stored and released from?
The juxtaglomerular apparatus in the wall of the afferent arterioles in the kidney
What does renin do?
Cleaves angiotensinogen to angiotensin 1
WHere is angiotensin 1 converted to active angiotensin 2?
In many tissues, especially lung
Role of angiotensin 2
Potent natural vasoconstrictor. V.short half life. Stimulates adrenal cortex to produce aldosterone
What effect does aldosterone have on the body?
It is a physiological mineralocorticoid. It acts on the kidneys and causes Na+ and thus water retention. Circulating blood volume increases.
Excessive aldosterone secretion
Conn’s syndrome
Causes of conn’s syndrome
Adrenocorticol adenoma
Micronodular hyperplasia
What effects does conn’s syndrome have on aldosterone and renin concentrations
Aldosterone increases, renin decreases to compensate.
Result of Conn’s syndrome
Gain sodium, lose potassium- muscular weakness, cardiac arrhythmias, metabolic alkalosis
How do you diagnose conn’s syndrome?
CT scan of adrenals in presence of metabolic abnormalities (increase in aldosterone, decrease in renin)
Tymour of the adrenal medulla, secretes vasoactive catecholamines- adrenaline and noradrenaline
Phaeochromocytoma
Effects of phaeochromocytoma
Pallor, headaches, sweating, nervousness, hypertension
How do you diagnose phaeochromocytoma?
24hr urine collection for adrenal metabolites
Treatment for phaeochromocytoma?
Surgery
Overproduction of cortisol by adrenal cortex- caused by oversecretion of ACTH
Cushing’s disease
How is cushing’s disease different from cushing’s syndrome?
Cushing’s syndrome- cotisol from any source.
Cusching’s disease- cortisol from adrenal cortex
Causes of cushing’s syndrome
Adrenocorticol neoplasm (usually an adenoma)
Pituitary adenoma
Paraneoplastic effect of other neoplasms