Cardiac

Question 1

Outline 2 key studies advocating the benefits of exercise for health

Answer 1

Paffenbarger- Harvard Alumni - 27% lower mortality if expending >2000 calories a day
Blair - fitness lowers mortality

Question 2

Quantify the benefit of increased MVPA

Answer 2

Extra 10 mins approximately - 10% reduction in mortality
150 MVPA a week - 30-40% less
750 - 50% less

Question 3

What conditions has strong evidence for the benefit of exercise?

Answer 3

CHD, stroke, HTN, hyperlipidaemia, type 2 diabetes Mellitus, metabolic syndrome, colon cancer, breast cancer, depression

Question 4

What conditions have moderate evidence for physical activity?

Answer 4

Hip fracture, lung cancer, endometrial cancer

Question 5

How much exercise should children do a day?

Answer 5

60 minutes minimum

Question 6

Define preload and afterload

Answer 6

Blood in ventricles before contraction - EDV

Blood in ventricles after contraction - ESV

Question 7

How do you calculate stroke volume, ejection fraction and shortening fraction?

Answer 7

Preload - afterload
((EDV - ESV) / EDV) * 100
((EDD - ESD / EDD) * 100

Question 8

What 3 factors affect HR

Answer 8

SNS
PNS
Adrenaline

Question 9

What 2 factors affect afterload?

Answer 9

Contractility

Systemic vascular resistance

Question 10

What 2 factors affect contractility?

Answer 10

Myocardial mass

Length-tension relationship of myocardial fibres

Question 11

What 4 factors affect preload?

Answer 11

Ventricular size
Venous size
Ventricular plasticity
Length-tension relationship of myocardial fibres

Question 12

What 2 factors affect venous return?

Answer 12

Blood volume

Pumps- muscular/respiratory/ventricular

Question 13

How much blood does the average adult have? Where is most of it?

Answer 13

5L

2/3 in veins

Question 14

What organs use the most blood at rest and during exercise?

Answer 14

27% liver and 22% kidneys

84% muscles

Question 15

What is the main blood vessel that determines vascular resistance? Outline the process of it’s vasodilation

Answer 15

Arterioles

Endothelium releases NO due to autonomic stimulation, which penetrates the smooth muscle and causes dilation

Question 16

What stimulates vasodilation?

Answer 16

Increased: NO, bradykinin, prostaglandins, K+, CO2, lactate
Decreased: pO2

Question 17

What stimulates vasoconstriction?

Answer 17

Increased SNS activity, releasing noradrenaline causing the alpha receptors to constrict

Question 18

How does exercise increase venous return?

Answer 18

Muscles contract
Increased SNS
Constriction of venous smooth muscle

Question 19

What is the effect of respiration on venous return

Answer 19

Expiration - increase thoracic pressure - push blood to heart
Inspiration - decrease thoracic pressure - pull blood to heart

Question 20

What affects afterload?

Answer 20

Volume of blood in arteries
Pressure in aorta
Compliance of aorta
Size of aorta/pulmonary arteries
Inertia of blood
Total peripheral resistance

Question 21

What is the effect of increased afterload?

Answer 21

Decreased stroke volume - increased preload
Decreased velocity of contraction and ejection
Increased O2 consumption

Question 22

What triggers the cardiovascular response to exercise? Where are they? How do they work?

Answer 22

Mechanoreceptors - muscle spindles - detect stretch and increase SNS
Metaboreceptors - muscle spindles - detect raised lactate/prostaglandin/phosphate/acidity and increases SNS
Baroreceptors - carotid sinus and aortic arch - increased arterial stretch and so lowers SNS, raises PNS thus lowering BP
Chemoreceptors - carotid sinus and aortic arch - raised CO2 cause raised SNS
Bainbridge reflex - more RA filling causes stretch causing increased SNS

Question 23

What are the branches of the left and right coronary artery?

Answer 23

Left anterior descending, left marginal artery, left circumflex

Right marginal artery and posterior interventricular arter

Question 24

What are the limits to coronary perfusion?

Answer 24

Tachycardia
Low diastolic pressure
Ischaemic heart disease

Question 25

Outline the process of atherosclerosis

Answer 25

Endothelial injury - fatty streak - macrophages invade and become foam cells - either: necrosis - calcium infiltrate - hardening of artery Or: growth factor - smooth muscle cover - stable/unstable plaque - occlusion

Question 26

What coronary artery is responsible for: anterior, septal, lateral, inferior, posterior, atrial MI?

Answer 26

``` LAD LAD LCx RCA RCx RCA ```

Question 27

What factors can lead to endothelial injury?

Answer 27

``` Normal wear and tear Fibrinogen Free radicals HTN a Turbulent flow Viral Carbon monoxide ```

Question 28

How does an unstable plaque lead to an MI?

Answer 28

Plaque ruptures - platelet aggregation - thrombus - occlusion - distal ischaemia

Question 29

Where would the MI be if the LAD, Right coronary/marginal or LCx was occluded?

Answer 29

Anterioseptal Inferior and right hand side Lateral

Question 30

How does an unstable angina differ from a stable angina?

Answer 30

Pain at rest/with less provocation and is more painful May have a thrombus May have biological markers

Question 31

What are the ECG changes associated with ischaemia, injury and infarction?

Answer 31

T wave inversion +/- ST depression T wave inversion and ST elevation Pathological Q waves

Question 32

Explain the mechanism behind ECG changes in ischaemia and injury

Answer 32

Slow to repolarise and remains more positively charged Delayed depolarisation and tall T waves due to potassium leakage from dead cells

Question 33

Outline the stages of change in an ECG after an MI

Answer 33

Normal - Tall T waves - ST elevation - Pathological Q waves and T wave inversion, less ST elevation - Pathological Q waves and upright T waves

Question 34

What is the 1 year mortality for an MI in: proximal LAD, middle LAD, distal LAD, Left circumflex, small inferior

Answer 34

``` 25 12 10 8 7 ```

Question 35

When do cells start dying and when are 80% and 100% of cells dead?

Answer 35

30 minutes 3 hours 6 hours

Question 36

Why do enzymes leak and what determines when they leak?

Answer 36

Cell dies so holes appear in the cell membrane | Size and solubility

Question 37

Name 3 enzymes that are looked for after an MI, the reference range, when they initially appear, when they peak and how long they remain elevated for

Answer 37

Troponin - <0.004ng - 4-6 hours - 12-24 hours - 6-8 days CK - 14-179IU - 4-6 - 12-36 - 3-4 CK-MB - <10.4ng - 4-6 - 12-24 - 2-3 LDH - 105-333IU - 8-12 - 48-72 - 7-10

Question 38

Initial treatment of MI

Answer 38

Morphine, oxygen (sometimes), GTN spray, aspirin

Question 39

List some medication to be taken after an MI

Answer 39

Heparin, beta blockers, ace inhibitors, calcium channel blockers, statins

Question 40

What is the WHO's definition of health?

Answer 40

A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity