hypertension & myocardial infarction

Question 1

what is hypertension?

Answer 1

• raised blood pressure above a population defined norm
• sustained systolic BP > 140mmHg and diastolic BP of > 90mmHg

Question 2

what is essential hypertension?

Answer 2

• high blood pressure that is not as a result of a medical condition

Question 3

what is** secondary** hypertension?

Answer 3

• high BP that is caused by another medical conditon eg problems with kidneys, arteries, heart or endocrine system etc

Question 4

what is malignant hypertension?

Answer 4

*** very high BP that comes rapidly **
* can lead to death in 1-2 years if left untreated
* often seen with renal failure & retinal haemorrhage

Question 5

compare** diastolic vs systolic pressure** & what is a normal value for these?

Answer 5

• systolic pressure refers to the amount of pressure experienced by the arteries while the heart is beating
• diastolic pressure refers to the amount of pressure in the arteries when the heart is at rest between beats
• normal value - under 120/80mmHg

Question 6

what are examples of pathologies that may cause secondary hypertension?

Answer 6

• renal - any cause of chronic renal failure eg renal artery stenosis
• endocrine - cushings, conn’s syndrome
• CVS
• neurologic - acute stress

Question 7

what is the equation for cardiac output?

Answer 7

CO= HR X SV

Question 8

what is the equation for BP?

Answer 8

BP= CO X TPR (total peripheral resistance)

Question 9

what is hypertension a risk factor for?

Answer 9

• stroke
• CVS disease
• renal disease

Question 10

what renal event may be the key initiating event in essential hypertension & why?

Answer 10

• reduced renal sodium excretion
• this will lead to increased fluid volume and cardiac output - which as a result will increase BP

Question 11

if the BP is lowered, what system does the renal system activate?

Answer 11

• the renin angiotensin aldosterone system
• by releasing renin

Question 12

as a result of the actions of the RAAS system in response to a low BP, what are the end effects?

Answer 12

• vasoconstriction
• retention of salt & water
• lead to increase in BP

Question 13

what might cause mineralcorticoid excess?

cause of secondary hypertension

Answer 13

• aldosterone producing adenomas
• bilateral adrenal hyperplasia
• ectopic aldosterone secretion

Question 14

what may cause corticosteroid excess?

cause of secondary hypertension

Answer 14

• cushings disease - pituitary gland tumour leading to excessive ACTH
• cushings syndrome - any other cause eg adrenal tumours, adrenal hyperplasmia, ectopic tumours releasung ACTH

Question 15

what may cause growth hormone excess in the body?

cause of essential hypertension

Answer 15

• pituitary gland produces too much GH

Question 16

what may cause catecholmine excess in the body?

cause of secondary hypertension

Answer 16

• tumours of chromaffin tissue of the adrenal medulla

Question 17

what is thyrotoxicosis?

Answer 17

• high level of thyroid hormones circulating in the body
• causes increased contactile activity of heart
• increases sympathetic activity - ie can cause vasoconstriction
• will raise systolic BP

Question 18

what are the vascular effects of HTN?

Answer 18

• accelerates atherosclerosis - ie hardening of arteries
• causes degenerative effects in vessel wall
• small vessel disease

Question 19

what is arterioloscelerosis?

Answer 19

progressive increase in the elastic or muscular components of the vessel wall which can be induced by hypertension

Question 20

what can occur to the left side vs right side of the heart as a result of HTN?

Answer 20

• left side - **concentric left ventricular hypertrophy ** - more common, due to response to systemic hypertension
• right side - right ventricular hypertrophy caused by disorders of pulmonary vasculature causing pulmonary hypertension

Question 21

what effect can an impaired blood flow to the heart result in?

Answer 21

ischaemia - which if it is very severe can cause infarction (,muscle death)

Question 22

what is ischaemia?

Answer 22

• imbalance between supply (perfusion) and demand of oxygenated blood to a tissue
• insufficient O2 and nutrients and inadequate removal of metabolites

Question 23

what is infarction?

Answer 23

tissue death due to ischaemia

Question 24

what are the risk factors for ischaemic heart disease ?

modifiable vs non mod

Answer 24

1. modifiable
   * hypertension
   * smoking
   * diabates
   * obesity
2. non mod
   * family history
   * genetics
   * age - risk increases with age
   * sex- men more likely

Question 25

what is angina?

Answer 25

• chest pain due to reduced blood flow to the heart
• due to lack of oxygen and build up of metabolites

Question 26

what is stable vs unstable angina?

Answer 26

• stable angina -the chest pains have a trigger eg when myocardial demand outweighs the perfusion eg during exercise … relief comes with rest or medication
• unstable - chest pain is more unpredictable - could happen with or without exercise / exertion - severe and transient reduction in cornary blood flow due to plaque

Question 27

what is acute coronary syndrome?

Answer 27

• a term that describes a range of conditions related to sudden, reduced blood flow to the heart
• eg unstable angina, acute MI & sudden death (regional myocardial ischaemia)

Question 28

what is myocardial infarction & what is it caused by ?

Answer 28

• heart attack
• caused by a decreased or complete cessation of blood flow to a portion of the myocardium
• platelets aggregate to the plaque on the vessel wall - coagulation pathwya is activated and a thrombus develops an atheromateous plaque which evolves to occlude the lumen

Question 29

what are the symptoms of myocardial infarction?

Answer 29

• chest pain
• LEFT arm pain
• short of breath
• sweaty
• dizzy
• rapid, weak pulse
• silent in elderly and diabetics

Question 30

how can you prevent myocardial infarction?

Answer 30

• stop smoking
• control BP
• reduce cholesterol and weight
• control of diabetes