CR

Question 1

P wave

Answer 1

Atrial depolarisation

0.08-0.1s

Question 2

QRS complex

Answer 2

Ventricular depolarisation

Question 3

T wave

Answer 3

Ventricular repolarisation

Question 4

PR interval

Answer 4

Delay at AVN

0.12-0.2s

Question 5

QT interval

Answer 5

Time when all the ventricular muscle is contracting

0.35-0.43s

Question 6

Physiology of AF

Answer 6

Atria experience chaotic signals and quiver

Only some APs pass through to ventricles giving irregular ventricular rhythm

Question 7

Causes of AF

Answer 7

Hypertension 
Heart attacks 
Abnormal valves
Hyperthyroid 
Sleep apnoea

Question 8

Symptoms of AF

Answer 8

Palpitations 
Reduced ability to exercise 
Fatigue 
Dizziness
Confusion 
Shortness of breath 
Chest pain

Question 9

ECG evidence for AF

Answer 9

No distinct P wave

Irregular R-R intervals

Question 10

Treatment for AF

Answer 10

Cardioversion to restore regular sinus rhythm
Thromboprophylaxis
Treatment of underlying cause if possible

Question 11

Why is there an increased chance of clots with AF?

Answer 11

Pooling of blood in atria
Stagnant blood more likely to clot
Clots can dislodge and be pumped out of the heart
Can block arteries in the circulation
Can cause stroke if reach cerebral arteries

Question 12

Rivaroxiban mode of action

Answer 12

Direct factor Xa inhibitor

Question 13

Vitamin K antagonists

Answer 13

Warfarin

Prevent formation of some clotting factors

Question 14

Heparins

Answer 14

Activate antithrombin III

Inhibits thrombin and factor Xa

Question 15

Speed of action potential in different parts of the heart

Answer 15

Atria = 0.5m/s
AVN = 0.05m/s
Bundle of his and bundle branches = 2m/s
Purkinje fibres = 4m/s

Question 16

Atrial contraction and exercise

Answer 16

10% of ventricular filling at rest
40% of ventricular filling in exercise
Less time for atrial filling in exercise
Atrial contractions needed to achieve maximum stroke volume

Question 17

Normal cardiac output

Answer 17

4. 9L/min for females

5. 6L/min for males

Question 18

Normal stroke volume

Answer 18

70ml in 70kg male

Question 19

Normal heart rate

Answer 19

60-100bpm

Question 20

Normal MAP

Answer 20

65-110mmHg

Question 21

Local mediators controlling vasodilation of arterioles supplying muscles

Answer 21

CO2, H+, K+, AMP, adenosine, NO, bradykinin

Question 22

Blood distribution to muscles at rest and in exercise

Answer 22

21% at rest

85% in exercise

Question 23

Mutation in Liddle syndrome

Answer 23

Mutation in C terminus of the ENaC channel
Inability for Nedd4-2 to bind
Channel cannot be marked for degradation
Increased activation of ENaC
Increased sodium retention
Increased water retention
Increased blood volume and therefore pressure

Question 24

Symptoms of Liddle syndrome

Answer 24

Early onset hypertension
Metabolic alkalosis
Muscle wasting (low potassium)

Question 25

Diagnosis of Liddle syndrome

Answer 25

Hypokalemia Elevated bicarbonate Supressed renin and aldosterone DNA probes

Question 26

Liddle syndrome inheritance pattern

Answer 26

Autosomal dominant

Question 27

Risk factors for hypertension

Answer 27

``` Old age Smoking Obesity Lack of exercise High salt intake Stress Ethnicity - more common in ACs Family history ```

Question 28

Treatment of hypertension

Answer 28

``` ACEIs Beta blockers CCBs Diuretics Renin inhibitors Angiotensin II receptor antagonists Aldosterone antagonists ```

Question 29

Complications of hypertension

Answer 29

``` Stroke Aneurysm Eye problems Ischaemic heart disease Kidney damage Left ventricular hypertrophy ```

Question 30

Amiloride

Answer 30

Potassium sparing diuretic | Targets ENaC channels in distal convoluted tubule

Question 31

How can hypertension lead to left ventricular hypertrophy?

Answer 31

Leads to increased afterload Heart has to pump harder to pump same volume of blood Muscle thickens in response

Question 32

What does aldosterone target?

Answer 32

ENaC and Na/K ATPase

Question 33

Why does an increased blood volume lead to increased blood pressure?

Answer 33

``` Increase in central venous pressure Increased venous return to the heart Increased preload Increased stroke volume and cardiac output Increased BP ```

Question 34

How is intrapleural pressure maintained?

Answer 34

Elastic recoil properties of the lung and chest wall Want to recoil against each other Creates negative pressure Surfaces stuck together by pleural fluid

Question 35

Types of pneumothorax

Answer 35

Primary spontaneous - rupture of bleb in absence of disease Secondary spontaneous - due to lung disease - COPD Traumatic - due to penetrating lung injury

Question 36

Pneumothorax risk factors

Answer 36

``` Male Tall Marfan syndrome Thin Young Atmospheric changes Lung disease Mechanical ventilation Scuba divers ```

Question 37

Pneumothorax symptoms

Answer 37

``` Chest pain Shortness of breath Tachycardia Tachypnoea Repeated dry coughing Cyanosis ```

Question 38

Pneumothorax diagnosis

Answer 38

``` Absent breath sounds on one side Tracheal deviation Unequal chest expansion JVP distension X ray - lung borders in lung space CT - can show lung collapse ```

Question 39

Pneumothorax treatment

Answer 39

Left alone Aspiration of air Surgery to close hole in pleura

Question 40

Why can't he fly

Answer 40

Cabin pressure reduced May be lower than intraplerual pressure Could cause lung to collapse again

Question 41

Asthma pathophysiology

Answer 41

``` Hyperactive and hyper-responsive airways Increased IL-4 production IgE production Degranulation of mast cells Inflammatory cytokine release Increased mucous secretion Mucous plugging ```

Question 42

Asthma triggers

Answer 42

``` Dust Pollen Animal hair Mould Smoke Asbestos Chemicals NSAIDs Aspirin Exercise Chest infections ```

Question 43

Risk factors for asthma

Answer 43

``` History of atopic disease Family history Inner city environment Obesity Viral infections in early childhood Smoking Early exposure to broad spectrum antibiotics ```

Question 44

Symptoms of asthma

Answer 44

``` Shortness of breath Coughing Wheezing Chest tightness Hypocapnia ```

Question 45

Symptoms of severe asthma attack?

Answer 45

SaO2 25bmp | Unable to complete sentences in one breath

Question 46

Diagnosis of asthma

Answer 46

Spirometry - reduced FEV1/FVC ratio

Question 47

Treatment of asthma

Answer 47

Beta2 agonists Muscarinic antagonists Inhaled corticosteroids

Question 48

Normal SaO2

Answer 48

>95%