Cardiac

Question 1

What are the layers of the blood vessel wall and what are they made of?

Answer 1

Tunica externa - collagen fibres
Tunica media - external elastic lamina & smooth muscle
Tunica intima - internal elastic lamina & basement membrane
Endothelium

Question 2

What makes up capillary walls?

Answer 2

Basement Membrane

Endothelial Cells

Question 3

What is diastole?

Answer 3

Relaxation phase - when heart is filling with blood

Typical 80mmHg

Question 4

What is systole?

Answer 4

Contraction

Typical 120mmHg

Question 5

Describe the cardiac cycle

Answer 5

Atrial Systole: A contracts. V relaxes. AV valve opens. SL valve closed

Early Ventricular Systole: A relaxes, V contracts, all valves closed

Late Ventricular Systole: A relaxed, V contracts, AV closed, SL opens

Early Ventricular Diastole: A relaxed. V relaxes. All valves closed. A passively filling.

Late Ventricular Diastole: A and V relaxed. AV opens. SL closed. A still filling passively.

Question 6

What do heart sounds ‘Lub dub’ correspond to?

Answer 6

Lub = AV valve closing
Dub = SL valve closing

Question 7

What is isovolumetric contraction?

Answer 7

Valves closed as ventricular depolarisation occurs and ventricles contract.
Build up of pressure as the valves are closed.
At about 80mmHg, there is enough pressure that the SL valve will open. This is when QRS finished.

Question 8

How is cardiac output calculated?

Answer 8

Heart Rate x Stroke Volume

bpm x ml/beat = ml/min

Question 9

What is cardiac output?

Answer 9

How much blood ejected by heart in 1 minute

Question 10

Name 4 factors for cardiac output

Answer 10

1. heart rate
2. preload
3. afterload
4. contractility

Question 11

How does heart rate affect cardiac output

Answer 11

chronotropic factors
positive =
sympathetic stimulation eg. adrenaline
drugs e.g atropine

negative=
parasympathetic eg acetlcholine
drugs eg adenosine

Question 12

What is preload with regards to cardiac output?

Answer 12

amount of blood entering ventricles in diastole
aka end diastolic volume

influenced by: venous return
blood volume
atrial contraction

Question 13

What is after load?

Answer 13

Afterload is in systole when ventricles contract?

It’s the resistance the ventricles must overcome in order to circulate blood

Question 14

How does contractility affect heart rate?

Answer 14

Ionotropic factors

How hard the myocardium is contracting for given preload.

Positive:
Sympathetic system - noradrenaline
drugs - dobutamine

Negative:
Parasympathetic - acetlycholineD
Drugs - beta blockers

Question 15

what can affect contractility of heart?

Answer 15

Increase:
High blood calcium
Glucagon
Thyroid hormone

Decrease:
Hypoxia
Hyperkalaemia (K+>5.2)

Question 16

What can affect the after load?

Answer 16

increase: 
hypertension
atherosclerosis
vasoconstriction
SL valve damage 

they all increase resistance therefore increase after load

Question 17

What can lower preload?

Answer 17

decrease thyroid hormone
decrease calcium
decrease body temp
hypoxia
abnormal pH

Question 18

What are 3 types of ASD?

Answer 18

1. Central defect (secundum type defect) - most common
2. Low defects of atrial wall (primum ASD) - alongside mitral valve deformity
3. High defects (sinus venous ASD) - commonly seen with abnormal R upper Lum vein position

Question 19

What are 3 functional categories of congenital heart disease?

Answer 19

1. R to L shunt

2 L to R shunt

3. Obstruction to flow.

Question 20

Describe R to L shunt

Answer 20

Blood shunted away from pulmonary circulation

Question 21

Give examples of R to L shunt

Answer 21

pulmonary atresia
trunks arteriosus
tricuspid atresia
HLHS

Question 22

What is treatment for R to L shunt?

Answer 22

Initially to maintain foetal circulation with prostin or create septal defect

Question 23

Describe L to R shunt?

Answer 23

High peripheral vascular resistance initially. Then 6-8 weeks this reduces and then get mixing. Hence it presents as late cyanosis.

Get increased pulmonary flow and therefore decreased systematic flow.

Question 24

What is Eisenmenger’s syndrome?

Answer 24

Start with L to R shunt but then as lung damage increases the shunt reverses and becomes R to L

Question 25

Give 3 examples of obstruction to flow

Answer 25

1. Co-arctation of the aorta
   Aortic Valvular stenosis
   Pulmonary stenosis

Question 26

What are two types of heart failure in children (and describe)

Answer 26

1. Diastolic

Overloaded blood = increased myocardium
Heart becomes an ineffective pump

2. Systolic

Heart muscle fails to work properly
Causes cardiomyopathy

Includes trauma, drug reaction, conduction issues

Question 27

What are signs of heart failure?

Answer 27

1. Cool peripheries
2. Weak pedal pulses
3. Poor feeding/weight gain
4. Tachypnoea/Tachycardia
5. Cardiomegaly/Hepatomegaly

Question 28

What are 2 ways that the heart adapts to preserve contractile state?

Answer 28

1. Intracardiac

If ventricles thicken then increased contractions = increased mitochondria = myocyte exhaustion = myocytic death = heart failure

2. Extracardiac

Hormones eg sympathetic system
Renin angiotensin aldoterterone system
Naturetic peptides

Question 29

What are 3 types of natriuretic peptides?

Answer 29

Atrial
Brain
C-type

Question 30

Where are ANP and BNP produced?

Answer 30

Secreted by myocardial cells in atrium in response to increased stretch

Question 31

What are natriuretic peptides marker of?

Answer 31

They are used as marker of treatment of heart failure.