Clinical Cardiovascular physiology

Question 1

4 clinical conditions that can result from ABP control being disrupted

Answer 1

Hypertension, Cardiac failure, Cardiac arrhythmia and circulatory shock

Question 2

what is hypertension?

Answer 2

ABP > 140/90 mmHg in humans.

Question 3

why is hypertension bad?

Answer 3

overwork of the heart, damage to blood vessels.
[leading to cardiac failure, cardiac arrhythmia and ischaemic damage (restriction of blood supply and therefore oxygen) to organs e.g. stroke]

Question 4

what physiological features does hypertension result from?

Answer 4

raised TPR and/or raised MSFP (failure of homeostasis).[treatment focuses on restoring to normal values]

Question 5

what is the cause of 90% of hypertension and what is it associated with?

Answer 5

‘essential hypertension’, no clearly defined cause.

Linked to genetic factors and age.

Question 6

what is the ~10% of hypertension with clear cause defined as?

Answer 6

secondary hypertension.

Question 7

what is the most common cause of secondary hypertension?

Answer 7

kidney disease. (kidneys important for hormonal control of circulatory volume through controlling angiotensin II levels.)

Question 8

what can also cause secondary hypertension (but not main cause)

Answer 8

excess adrenaline from pheochromocytoma tumour (activating sympathetic receptors)

Question 9

what can be used to reduce MSFP to treat secondary hypertension?

Answer 9

reducing circulatory volume (with diuretics) and hormone antagonists blocking renal signalling

Question 10

example of hormone antagonists that block renal signalling

Answer 10

ACE Inhibitors

Question 11

what can be used to reduce TPR as treatment for secondary hypertension?

Answer 11

drugs causing arteriolar vasodilatation e.g. Ca2+ channel blockers such as nifedipine

Question 12

what lifestyle changes can also help treat hypertension ?

Answer 12

exercise; lowers mean resting blood pressure. (even through raises ABP during the exercise)

Question 13

why is it important to treat secondary hypertension ?

Answer 13

reduces risk of; stroke, heart disease, heart failure, dementia and death

Question 14

why is it important to make sure patients with hypertension understand why they are being treated?

Answer 14

can be asymptomatic, drugs can cause side effects that make them feel less well. (even tho preventing fatal harm) [also hypotension is symptomatic]

Question 15

what is it pessary to ensure when doing a trial for new hypertension treatment?

Answer 15

study design does not influence stress levels of participants as this can affect ABP

Question 16

what is atherosclerosis ?

Answer 16

build up of inflammatory lipid deposits beneath endothelium of blood vessels. Progress to form fibrous and calcific layers

Question 17

why does atherosclerosis cause problems?

Answer 17

• Narrows blood vessels and resistrics flow
• endothelial damage which promotes clotting (thrombosis, local and distant)
• weakening blood vessel walls, leading to aneurysm.

Question 18

how is hypertension linked to atherosclerosis ?

Answer 18

hypertension accelerates the development of atherosclerosis by damage to endothelium (other risk factors; obesity, diabetes and smoking)

Question 19

circulatory effects of hypertension

Answer 19

increase risk of atherosclerosis and abnormal blood vessels might rupture under pressure.

Question 20

what are coronary arteries?

Answer 20

arteries that supply the HEART with blood

Question 21

cardiac effects of hypertension

Answer 21

atherosclerosis affects coronary arteries, which can result in cardiac ischaemia (patient feels pain)

Question 22

what des ischaemia literally mean?

Answer 22

stopping blood. (leads to inadequate oxygen supply)

Question 23

why is cardiac ischaemia a particular problem in hypertension?

Answer 23

heart has to pump blood into arteries, raised arterial pressure increases work demand for heart

Question 24

what is hypertrophy?

Answer 24

enlargement of cells and increase in mass

Question 25

difference between eccentric hypertrophy and concentric hypertrophy in the heart (eccentric and concentric)

Answer 25

eccentric; due to exercise, ventricular volume INCREASES along with the muscle mass. concentric; muscle expands inwards, DECREASES ventricular volume.

Question 26

3 major problems due to concentric hypertrophy

Answer 26

- increased myocardial oxygen demand - Diastolic dysfunction, cardiac filling and stroke volume is impaired - increased risk of cardiac arrhythmias

Question 27

what can concentric hypertrophy lead to?

Answer 27

ventricular dilatation - heart can't empty fully (systolic dysfunction)

Question 28

diastolic vs systolic dysfunction

Answer 28

diastolic - less compliant to filling | systolic - less contractile

Question 29

what does diastolic and systolic dysfunction produce?

Answer 29

cardiac failure

Question 30

what is cardiac failure?

Answer 30

cardiac output that is inadequate for the body's needs. | CO insufficient to maintain body target arterial blood pressure

Question 31

how do normal responses to low ABP fair if it is due to heart failure?

Answer 31

Make it worse, responses make heart work harder and can lead to oedema

Question 32

what do Pharmacological treatments aim to do for low ABP cause by HEART FAILURE

Answer 32

block natural responses low ABP.

Question 33

what is a myocardial infarction?

Answer 33

heart attack, occurs when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle.

Question 34

what does cardiac arrhythmia represent?

Answer 34

disorder in cardiac rhythm and/or failed co ordination of individual myocytes within each chamber.

Question 35

what can be the cause of cardiac arrhythmia?

Answer 35

hypertension, lead to heart failure and produce disordered conduction pathways. (also infarction and ischema)

Question 36

what is the most common cardiac arrhythmia?

Answer 36

atrial fibrillation

Question 37

how does atrial fibrillation arise?

Answer 37

irregular heart beat, pacemaker function is lost

Question 38

how does atrial fibrillation affect cardiac output?

Answer 38

reduces it by impairing ventricular filling

Question 39

what is the most common terminal event in heart failure and following myocardial infarction?

Answer 39

VENTRICULAR arrthymias.

Question 40

what is (circulatory)shock ?

Answer 40

if cardiac output is insufficent to supply metabolic substrates for aerobic respiration to all tissues, life-threatening medical emergency

Question 41

different types of (circulatory) shock

Answer 41

- hypovolaemic shock (loss of circulating volume) - cardiogenic shock (cardiac pathology) - distributive shock (fall in vascular tone and leaking of plasma, similar to hypovolaemic)

Question 42

what can distributive shock be caused by?

Answer 42

septicaemia or anaphylaxis due to failure of sympathetic intervention.

Question 43

typical signs of shock

Answer 43

hypotension, tachycardia, reduced organ perfusion such as low urine output and loss of consciousness