9. Background Science

Question 1

What is end diastolic volume

Answer 1

the volume of blood in the ventricles before contraction

Question 2

What is preload

Answer 2

end diastolic pressure which is stretching the walls of the ventricle to their greatest dimensions

Question 3

stroke volume

Answer 3

the volume of blood ejected from the heart per heart beat

Question 4

what is the stroke volume proportional to

Answer 4

the preload

Question 5

what is the frank starling curve

Answer 5

A greater end diastolic volume would increase the contractile strength of the ventricles and will increase stroke volume

Question 6

what agents can;

a) increase the contractility of the heart
b) decrease the contractility of the heart

Answer 6

a) catecholamines and calcium

b) acidosis and some negatively inotropic drugs such as anaesthetic agents

Question 7

in terms of the frank starling curve what happens in heart failure

Answer 7

it has reduced contractility which increases the end diastolic volume and so eventually the heart cannot respond to increasing end diastolic volume and it will decompensated

Question 8

eventually stroke volume will decrease which increases venous pressure which causes ………

Answer 8

fluid to leak out of the blood into the alveolar interstitial fluid resulting in pulmonary oedema

Question 9

what is the difference between systolic and diastolic heart failure

Answer 9

systolic is when the heart cant pump hard enough

diastolic is when the ventricles aren’t filling enough/abnormal filling

Question 10

name some causes of systolic left sided heart failure

Answer 10

ischemic heart disease damaging the myocardium
long stand hypertension (hypertrophy due to increase in atrial pressure demand)
dilated cardiomyopathy to try and increase preload

Question 11

name some causes of diastolic right sided heart failure

Answer 11

aortic stenosis 
long standing hypertension 
hypertrophic cardiomyopathy 
restrictive cardiomyopathy 
less blood flow from the heart activates the RAAS system causing fluid retention--> leaking

Question 12

name some causes of left sided heart failure

Answer 12

note that is. often caused by LHF

• right to right atrial shunt such as atrial septal defect and ventricular septal defect
• in chronic lung disease, hard to exchange O2 leading the hypoxia –> pulmonary arteriole contraction leading to hypertrophy and failure of the right side eg cor pulmonale

Question 13

name some causes of mitral regurgitation

Answer 13

rheumatic heart disease
ischaemic heart disease - assoicated wtih papillary muscle rupture
valvular vegetations- as in patients with endocarditis
physiological mitral value regurgitation due to dilated left atrium

Question 14

What does jugular venous pressure (JVP) indirectly measure

Answer 14

the pressure in the right atrium

Question 15

what are the common causes of increased JVP

Answer 15

heart failure
fluid overload
constrictive pericardiits
carhadc tapenade

Question 16

how many JVP pulses are in one heart beat

Answer 16

2

Question 17

how can you distinguish the JVP from the carotid pulse

Answer 17

JVP has 2 pulses per heart beat and there is no palpable pulsation

Question 18

how can you illicit a raised JVP

Answer 18

by doing the hepatojugular reflex which is where you press over the liver (RUQ)

Question 19

Draw out the JVP waveform and then describe what the following waves are;

1. A wave
2. C wave
3. V wave
4. X descent
5. Y descent

Answer 19

1. RA contraction
2. RV contraction
3. RA is full - occurs in late systole when there is increased blood in the RA from venous return
4. Atria relax (1st one) and then RV contract and atria expand (2nd one)
5. Opening of the tricuspid value

Question 20

in the JVP wave form what do the following abnormalities indicate

1. absent A wave
2. Large A wave
3. Large V wave

Answer 20

1. AF
2. right ventricular hypertrophy or tricuspid stenosis
3. Tricuspid regurgitation

Question 21

when grading murmurs what does grade 1-4 mean

Answer 21

Grade 1: murmur is only heard on listening intently for some time

Grade 2: Faint murmur that is heard immediately on auscultation

Grade 3: A loud murmur with no palpable thrill

Grade 4: A loud murmur with a palpable thrill

Question 22

Why would anaemia cause a heart murmur

Answer 22

there is decreased blood viscosity

Question 23

why would valvular stenosis, coarctation of the aorta and ventricular septal defect cause a heart murmur

Answer 23

there is decreased diameter of the vessel, valve or orifice

Question 24

why would a hyper-dynamic state eg sepsis or hyperthyroidism cause a heart murmur

Answer 24

there is increased velocity of blood through normal structures

Question 25

name some systolic murmurs

Answer 25

aortic stenosis 
mitral regurgitation 
(also pulmonary stenosis and tricuspid regurgitation )
ventricular septal defect
Aortic outflow tract obstruction

Question 26

name some diastolic murmurs

Answer 26

aortic regurgitation
mitral stenosis
(also pulmonary regurgitation and tricuspid stenosis)

Question 27

name a continuous murmur

Answer 27

patent ductus arteriosus