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1 CVS Flashcards

1
Q

Rate of diffusion depends on 3 factors, these are:

A
  1. Area available for exchange
  2. Concentration gradient
  3. Diffusion resistance ie. nature of the molecule, the barrier, the path length
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2
Q

The area available for exchange depends on…

A

capillary density

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3
Q

Which tissues will have higher capillary density?

A

Metabolically actuve tissues

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4
Q

How is the concentration gradient (necessary for diffusion) maintained?

A

By sufficient blood flow, bringing more of the substance to the capillary bed.

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5
Q

The rate of the blood flow determines the …. …. driving O2 diffusion into the cells

A

Concentration gradient.

So tissues that are more metabolically active need a higher blood flow

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6
Q

the higher the rate of metabolism, the … the demand for O2 and nutrients.

A

greater

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7
Q

Increases in metabolism must be met by increase in … …

A

blood flow

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8
Q

the rate of blood flow is known as the…

A

perfusion rate

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9
Q

The brain needs what sort of blood flow? description and value

A

The brain needs HIGH, CONSTANT flow.

approx. 0.5 ml/min.g

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10
Q

The heart muscle needs what sort of blood flow? description and value

A

The heart need high flow which increase during exercise.

Approx. 0.9-3.6 ml/min.g

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11
Q

Kidney need what sort of blood flow? description and value

A

Kidneys need HIGH, CONSTANT flow.

Approx. 3.5 ml/min.g

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12
Q

What is the approx. cardiac output for a 70kg male? And what if he’s exercising?

A

5 L/min

Can go up to 25 L/min!

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13
Q

What are the layers of the pericardium and heart wall?

A 
Fibrous layer - non distensable
Parietal layer - outer serous cavity
Pericarial cavity
Visceral layer - Inner serous layer, = epicardium
Myocardium
Endocardium
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14
Q

What is cardiac tamponnade? What is the treatment?

A

It is compression of the heart due to fluid accumulation in the pericardial cavity. The heart will no longer be able to fill correctly.
May need to do a pericardiocentesis, ie. remove fluid to relieve compression (+ test liquid)

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15
Q

What is heart compression due to fluid build-up in percardial cavity called?

A

cardiac tamponnade (ttt= pericardiocentesis)

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16
Q

Where is the pericardial transverse sinus located? Why is it clinically relevant?

A

Behind the ascending aorta and pulmonary trunk. (but in front of/not as far as the superior vena cava)
It is a useful landmark if we need to clamp the aorta and install extracorporeal circulation, here in particular heart-lung bypass (also called CPB cardiopulmonary bypass)

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17
Q

Where is the oblique sinus located? Why is it clinically relevant?

A

On the posterior surface of the heart, just below where the 4 pulmonary veins meet.
It is clinically relevant as may need to place swab there to avoid blood accumulation suring surgery.

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18
Q

What is a heart lung bypass and where are it’s cannulae placed?

A

A heart-lung circulation is a sort of extracorporeal circulation.
The aortic cannula is place just above the clamped aorta (clamp is placed just above the pericardial transverse sinus) and the venous cannula is placed in the inferior vena cava and superior vena cava.

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19
Q

Where do the left and right coronary arteries originate from?

A

They originate at the very base of the ascending aorta.

  1. Right aortic sinus
  2. Left aortic sinus
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20
Q

Where does the Right coronary artery run?

A

Along the right atrium, between right atrium and right ventricle.

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21
Q

Where does the left coronary artery run, and which are its major branches?

A

It runs behind the left auricle, and its major branches are

  1. left circumflexe artery
  2. left anterior descending (or interventricular) artery
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22
Q

What is another name for the Left Anterior Descending artery?

A

Interventricular artery

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23
Q

Where does the left anterior descending artery run?

A

between the right and left ventricles

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24
Q

What are the left and right aortic sinuses?

A

They are the origins of the right and left coronary arteries.

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25
Q

Which coronary artery is most likely to get blocked in myocardial infarction?

A

The left anterior descending coronary, also called anterior interventricular artery, or even the “widow maker”

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26
Q

Awhat is the “widow-maker” and why is it bare that name?

A

It is a coronary artery that arises from the left coronary artery.
Also called: left anterior descending or interventricular.

It is called the widow maker as it is the mist common coronary to be affected in MIs

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27
Q

Where does the right marginal artery arise from and where does in run?

A

The right marginal artery arises from the rught coronary artery and it runs along the inferior edge of the right ventricle toward the apex of the heart

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28
Q

What is the coronary sinus?

A

It is where all the cardiac veins drain to, before joining the right atrium

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29
Q

From which vessels does the right atrium receive blood?

A

2 vena cava (sup/inf) and th coronary sinus

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30
Q

What happens if a major coronary artery gets blocked?

A

MI

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31
Q

4 major heart valve names and location?

A
  1. Mitral - LA-LV
  2. Tricuspide - RA-RV
  3. Aortic - LV-aorta
  4. Pulmonary - RV-pulmonary trunk
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32
Q

What is responsible for S1 sound?

A

Closing of mitral and tricuspide valves

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33
Q

What is responsible for S2 sound?

A

closing of aortic and pulmonary valves

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34
Q

In which circumstances do you hear an S3 sound?

A
  1. Children - non-pathological
  2. Adults - pathological, associated with heart failure.

S3 would occur during rapid filling phase of the cardiac cycle, this is phase 6.
Normally filling should be silent in adults.

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35
Q

What are capacitance vessels and what function do they serve?

A

They are venous vessels that enabke the system to vary the amount of blood pumped around the body. They vessels will accomodate the volume if needed.

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36
Q

What are resistance vessels and which function do they serve?

A

They restrict blood flow to drive supply to active tissues.
They will adapt the % of cardiac output going to various tissues according to the activity.
It is arterioles that are major resistance vessels!

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37
Q

Systemic circulation is a … pressure circuit

A

HIGH

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38
Q

Pulmonary circulation is a … pressure circuit

A

LOW

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39
Q

Output of left and right sides over time must be …

A

equal

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40
Q

What is the typical pressure in right atrium?

A

0-4 mmHg

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41
Q

What is the typical pressure in the left atrium?

A

8-10 mmHg

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42
Q

What is the typical pressure in the right ventricle?

A

25 systole/4 diastole

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43
Q

What is the typical pressure in the left ventricle?

A

120 systole/ 10 diastole

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44
Q

What are the typical pressures in the aorta?

A

120 systole / 80 diastole

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45
Q

What are the typical pressures in the pulmonary artery?

A

25 systole / 10 diastole

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46
Q

What is systole?

A

Contraction and ejection of blood from ventricles

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47
Q

What is Diastole?

A

relaxation and filling of the ventricles

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48
Q

Which of the ventricles is more muscular?

A

Left, higher pressures to deal with!

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49
Q

What is the average stroke volume for a 70kg male at rest?

A

70 ml/beat

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50
Q

What is stroke volume?

A

It is the volume that the ventricles eject at each heart contraction

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51
Q

How does cardiac muscle contraction relate to other muscle tyoes?

A

They are LONG last for the duraitin of a single contraction 280ms. (makes sense as needs to be transmitted to all myocytes)

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52
Q

Which valves have papillary muscles and cordae tendinae?

A

Mitral and tricuspide to avoid prolapse (during systole) under pressure into the atria.

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53
Q

Give a few characteristics of cardiac muscle cells

A
  1. They are a specialised form of muscle
  2. They are individual cells, not a true syncytium, but they are interconnected by gap junctions
  3. They have sarcomeres, t-tubules
  4. Their ends branch into two
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54
Q

Hoe long does a cardiac action potential last and how does this compare to other muscle types?

A

~280ms

This is LONG compared to other muscle types

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55
Q

What does the opening/closing of valves depend on?

A

Opening/c’osing of valves depends solely on differential blood pressure on each side.
This means that they function mechanically.

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56
Q

What is the runction of papillary and cordae tendinae

A

They prevent valve prolaspe into atria when they close.

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57
Q

What sort of cells make up the sinoatrial node?

A

The are NOT nervous cells but specialised myocytes.

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58
Q

Why is the atrioventricular node important?

A

It is important because it delays transmission of the AP to the ventricules. we don’t want ventricle contraction at the same time as the atria, as we need ventricles to fill during atrial contraction.

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59
Q

How can we describe the “shape” of the heart contraction?

A

Like an 8.
It starts at the apex, then goes upwards and twists.
Also, AP conduction goes from endocardium to epicardium; ie. in to out

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60
Q

How many phases are there in the cardiac cycle?

A

7

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61
Q

What are the phases of the cardiac cycle in the correct order?

A
  1. Atrial contraction
  2. Isovolumetric contraction
  3. Rapid ejection
  4. Reduced ejection
  5. Isovolumetric relaxation
  6. Rapid filling
  7. Reduced filling
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62
Q

Which of the cardiac cycle phases are systolic?

A
  1. Isovolumetric contraction
  2. Rapid ejection
  3. Reduced ejection
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63
Q

Which of the cardiac cycle phases are part of diastole?

A
  1. Isovolumetric relaxation
  2. Rapid V filling
  3. Reduced V filling
  4. Atrial contraction
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64
Q

What is the total duration of a cardiac cycle at 67 beats/min?

A

0.9 seconds

65
Q

Which of diastole and systole can change in duration to adapt to heart rate?

A

Diastole can shorten.

systole will always be te same length, (ie. at 67 betas/min, systole is 0.55 s)

66
Q

For which side of te heart is the wiggers diagram typically plotted?

A

only the left!

67
Q

If we were to draw a wiggers diagram for the right side of the heart, what differences would we see compared to the left?

A

It would be very similar to the typical Wiggers diagram for the left, only at lower pressures.

68
Q

1 cardiac cycle is how many systoles and diastoles?

A

1 systole

1 diastole

69
Q

What are the axis of a Wiggers diagram?

A
  1. Upper part: Pressure/time [s]

2. Lower graph: Volume/time [s]

70
Q

What different curves does a wiggers diagram comprise?

A
  1. Aortic pressure
  2. Left atrial pressure
  3. Left ventricular pressure
  4. Left ventricular volume
  5. Electrocardiogram
  6. Phonocardiogram
71
Q

What is the phase 1 of the vardiac cycle?

A

Atrial contraction

72
Q

What is the phase 2 of the cardiac cycle?

A

isovolumetric contraction

73
Q

What is the phase 3 of the cardiac cycle?

A

Rapid ejection

74
Q

What is phase 4 of the cardiac cycle?

A

Reduced ejection

75
Q

What is phase 5 of the cardiac cycle?

A

Isovolumetric relaxation

76
Q

What is phase 6 of the cardiac cycle?

A

Rapid filling

77
Q

What is phase 7 of the cardiac cycle?

A

Reduced filling

78
Q

What happens during phase 1 of the cardiac cycle?

A

This phase is atrial contraction.

  • A wave: rise in LA pressure due to atrial contraction
  • Ventricular volume rises, but only a little. Atrial contraction only accounts for the final 10% of ventricular filling. This value rises with age and exercise.
  • This phase starts with P wave. P wave is an ECG wave that indicates onset of atrial depolarisation.
79
Q

What is the “A wave” and on which curve does one see it?

A

The A wave is a left atrial pressure wave.

It is due to atrial contraction causing an increase in atrial pressure.

80
Q

What drives ventricular filling?

A

80% on ventricular filling is due to residual blood from previous contraction and passive falling from atria into ventricle.
10-20% only of filling is due to atrial contraction

81
Q

What is the EDV.

A

End Diastolic Volume.

  • this is the maximal volume the ventricule will hold
  • typically 120ml
82
Q

What is the typical value for EDV?

A

120ml

83
Q

Which valves are open/closed during phase 1 of the cardiac cycle?

A

Mitral/tricuspide valves are open

Aortic/pulmonary valves are closed

84
Q

What happens during isovolumetric contraction?

A

Starts with mitral valve closing as ventricular pressure exceeds atrial pressure. So both valves gating the ventricle are closed, and the ventricle contracts.

  • Closure of the mitral valve causes C wave in atrial pressure curve
  • Ventricular pressure rises rapidly as ventricle contracts
  • EDV doesn’t vary as ventricular volume is fixed by closed valves
  • QRS complex in ECG curve signifies onset of ventricular depolarisation
  • S1 due to closure of mitral and tricuspide valves
85
Q

What is “QRS”?

A

QRS are 3 segments of the ventricular contraction fluctuation on the ECG curve.

86
Q

What is the C wave and on which curve of a a Wiggers diagram is it observed?

A

C wave corresponds to a small atrial pressure increase following mitral/tricuspide valve closure. It is consequently observed on the atrial pressure curve.

87
Q

During which phase of the cardiac cycle is S1 heard and what does it result from?

A

S1 is heard during isovolumetric contraction phase (as it starts with mitral valve closure which is responsible for S1 sound)

88
Q

During phase 2 of the cardiac cycle, which valves are open/closed

A

All closed!

89
Q

What occurs during phase 3 of the cardiac cycle?

A
  • aortic valve opens
  • rapid decrease in ventricular volume
  • atrial pressure decreases! Why? because as the ventricles contract, the atrial base is pulled down, freeing up more space, thus decreasing the pressure inside the atrium = X descent
90
Q

What is the X descent, and in whihc phase does it occur?

A

X descent is a decrease in atrial pressure during rapid ejection (ph. 3) due to the atrial base being pulled down when ventricle contracts thus widening the atrium.

91
Q

What occurs during phase 4 of the cardiac cycle?

A
  • rate of ejection begins to fall as ventricle is repolarised, ecause of the decline in tension
  • atrial pressure gradually rises due to continued venous return from the lungs = V wave of atrial pressure curve
  • ECG curve: T-wave, it depicts the repolarisation of ventricle
92
Q

What occurs during phase 5 of the cardiac cycle?

A
  • pressure in ventricle has fallen sufficiently for aortic/ pulmonary valve to close
  • pressure falls rapidly
  • volume stays identical as valves are all shut
  • ventricular volume is fixed on ESV
  • dicrotic notch: on the aortic pressure curveis caused by valve closure
  • S2! from closure of aortic/pulmonary valves
93
Q

What is the dicrotic notch and on which curve of Wiggers diagram is it observed?

A

It it a short rapid wave in aortic pressure due to valve closure.

94
Q

What is end systolic volume and when is it observed?

A
  • end systolic volume ESV is the lowest ventricular volume observed during the cardiac cycle, ie after ejection
  • it is observed on the ventricular volume curve
95
Q

What is stroke volume, and how csn it be expressed using volumes?

A

Stroke volume is the volume of blood ejected at each ventricular contraction.
It is calculated: EDV - ESV

96
Q

What is the typical stoke volume?

A

~80 mmHg

97
Q

What occurs during phase 6 of the cardiac cycle?

A

Phase 6 = Rapid filling

  • Starts with mitral valve opening
  • Fall in atrial pressure called the “Y-descent” (this only appear as a small drop !)
  • ventricular volume rises importantly
  • ventricular pressure stays low and constant
  • MAY hear S3 sound. If child, then normal. If adult, then sign of heart failure, as ventricle is still containing a lot of blood and the filling form atria is abnormal.
98
Q

What occurs during phase 7 of the cardiac cycle?

A

Phase 7 = reduced filling

  • rate of filling slows down = diastasis, so ventricular volume stabilises as it reaches its inherent relaxed volume
  • at rest the ventricules are 90% full by the end of phase 7.
99
Q

What 2 sorts of abnormal valve function can occur?

A
  1. Stenosis

2. Regurgitation

100
Q

What is valvular stenosis and its general consequences?

A

Stenosis is when the valve doesn’t open properly causing obstruction to blood flow.

101
Q

What is valvular regurgitation and its general consequence?

A

Regurgitation is when a valve does not shut properly resulting in back-leakage of blood when valve should actually be closed.

102
Q

Which valves are the most commonly affected by valvulopathies?

A

Mitral and aortic

103
Q

What are 3 common causes for aortic valve stenosis?

A
  1. Degenerative - ie. old age calcification/fibrosis
  2. Congenital - the valve is bicuspide instead of tricuspide
  3. Chronic rhumatic inflammation causes commissural fusion
104
Q

What are the 3 consequences of aortic valve stenosis?

A
  1. Increased LV pressure, so heart hypertrophy as has to make a greater effort on ejection
  2. Left sided heart failure causing syncope and angina
  3. The blood is now pushed through a smaller opening and this can damage the RBCs = shear stress, with the consequence of “Microangiopathic haemolytic anaemia”
105
Q

What are 2 main causes of aortic valve regurgitation?

A
  1. Aortic root dilation - so leaflets are further apart and can no longer obstruct passage
  2. Valvular damage by endocarditis such as rhumatic fever
106
Q

What is rheumatic fever and how does it affect the heart?

A

Rheumatic fever is an inflammatory disease that can affect heart, joints, skin and brain.
The disease typically develops two to four weeks after a streptococcal throat infection.
The damaged valves cause REGURGITATION which may result in heart failure, atrial fibrillation and infection of the valves.Regurgitation can occur at all valves, but most commonly aortic or mitral.

107
Q

What happens in aortic valve regurgitation?

A
  • Blood flows back into LV during diastole
  • Increase in stroke volume
  • Systolic pressure increases
  • Diastolic pressure decreases
  • Bouding pulse (head bobbing, Quinke’s sign)
  • LV hypertrophy
108
Q

What is a bounding pulse?

A

It occurs when PULSE PRESSURE IS INCREASED.
A bounding pulse occurs when the aortic valve is incompetent leading to regurgitation. The stroke volume is higher, and the heart beats stronger to eject the increased volume. Sometimes, head of patient moves with each beat = head bobbing

109
Q

What sound does one hear in patient with aortic valve regurgitation?

A

early decrescendo diastolic murmur after S2

110
Q

What sound does one hear whne patient has aortic valve stenosis?

A

Crescendo-decrescendo murmur

111
Q

What are 4 common causes of mitral valve regurgitation?

A
  • myxomatous degeneration of chordae tendinae and papillary muscles, that are then weakened and lead to valvular prolapse.
  • damage to papillary muscle after heart attack
  • left sided heart failure leads to LV dilation which can stretch valve
  • Rheumatic fever can lead to leaflet fibrosis which disrupt seal formation
112
Q

What happens during mitral valve regurgitation?

A
  • Some blood flows back into LA increasing PRELOAD
  • preload is increased as there is now more blood entering the ventricle in subsequent cycles.
  • can lause LV hypertrophy
113
Q

What is a Quinke sign?

A

This is when the nail bed flushes and then goes pale with each heart beat. It occurs in some cases of aortic valve regurgitation, as a consequences of increased stroke volume

114
Q

What is the most common cause of mitral valve stenosis?

A
  • 99.9% rheumatic fever!
115
Q

What sound is heard in mitral valve regurgitation?

A

Holosystolic murmur

116
Q

What are the consequences of mitral valve stenosis?

A
  • it is harder for blood to flow LA => LV
  • So LA pressure increases, causing…
    1. Pulmonary oedema, dyspnea, pulmonary hypertension => RV hypertrophy
    2. LA dilation
    => atrial fibrillation => thrombus formation
    => oesophagus compression => dysphagia
117
Q

Which sort of valvulopathy can cause pulmonary oedema and RV hypertrophy?

A

Mitral valve stenosis

118
Q

Which sort(s) of valvulopathies cause LV hypetrophy?

A

Aortic valve regurgitaiton

Aortic valve stenosis

119
Q

Which type of valvulopathy can cause anaemia?

A

Aortic valve stenosis

120
Q

In which valvulopathy can one see Dysphagia due to the oesophagus being compressed?

A

Mitral valve stenosis

Less blood can flow into LV, so build up in LA, causing LA dilation which can impinge on oesophagus.

121
Q

What is plasma?

A 
It is the fluid collected from un clotted blood.
Ie. one of 3 layers of centrifuged blood
- plasma
- buffy coat (white blood cells)
- RBCs

Blood plasma is a straw colored liquid component of blood that normally holds the blood cells in whole blood in suspension; this makes plasma the extracellular matrix of blood cells. It makes up about 55% of the body’s total blood volume.[1] It is the intravascular fluid part of extracellular fluid (all body fluid outside of cells). It is mostly water (up to 95% by volume), and contains dissolved proteins (6–8%) (i.e.—serum albumins, globulins, and fibrinogen),[2] glucose, clotting factors, electrolytes (Na+, Ca2+, Mg2+, HCO3−, Cl−, etc.), hormones, carbon dioxide (plasma being the main medium for excretory product transportation) and oxygen. Plasma also serves as the protein reserve of the human body. It plays a vital role in an intravascular osmotic effect that keeps electrolytes in balanced form and protects the body from infection and other blood disorders.

122
Q

What is serum and why is it different to plasma?

A

Serum is the liquid phase collected from clotted whole blood.
So serum is plasma without clotting factors especially fibrinogen!

123
Q

We say coronary arteries but … veins

A

cardiac

124
Q

What is by far the most common cause eased whole blood viscosity?

A

Multiple myeloma

125
Q

What is CABG?

A

Coronary Artery Bypass Grafting

  • type of surgery that improves blood flow to the heart.
  • treatment for coronary heart disease
  • CHD is a disease in which a waxy substance called plaque builds up inside the coronary arteries
  • Over time the plaques can harden (and obstruct lumen) or rupture (blood clot at plaque surface obstructing lumen)
126
Q

What is heparin?

A

Heparin is an anticoagulant

127
Q

What us peripheral resistance?

A

It is the resistance opposed by arterioles

128
Q

What can change in the blood for it to become viscous?

A
  1. Plasma viscosity can increase leading to whole blood viscosity increase
  2. RBC, platelet or white blood cell increase can lead to whole blood viscosity increase
129
Q

What does sludging mean?

A

Intravascular slowing or clumping of RBCs

130
Q

How does viscosity vary with temperature and how does this relate to the body peripheries?

A

Viscosity increases with the cold. And peripheries are colder, so viscosity of blood increases in body peripheries

131
Q

Why does myeloma cause blood viscosity to increase?

A

Become there is a huge amount of protein in the blood.

The proteins in question are serum immunoglobulins.

132
Q

Is turbulent or laminar flow “normal”?

A

laminar

133
Q

What is laminar flow?

A

It is the flow of blood in streamlines with each layer of blood remaining the same distance from the wall.
When laminar flow occurs, the VELOCITY of blood in the center of the vessel is greater than that towards the outer edge creating a parabolic profile.

134
Q

What is turbulent flow?

A
  • blood flowing in all directions in the vessel and continually mixing within the vessel
  • when the rate of blood flow becomes too great (flow is NOT velocity)
  • when blood passes by an obstruction in a vessel
  • when blood makes a sharp turn
  • when it passes over a rough surface (like atheroma)
  • when there is increased resistance to blood flow
135
Q

In which clinical situation is blood flow turbulent?

A

Anaemia! The heart rate is increased and so is cardiac output to compensate lack of oxygen being delivered to tissues.
The turbulent flow may lead to murmur!

136
Q

What are the units of flow?

A

volume/time

137
Q

What are the units of velocity?

A

distance/time

138
Q

Do flow and velocity necessarily change together and in same direction?

A

No!

Flow can decrease and velocity increase, it is the case in stenosis for example!

139
Q

In which case does flow decrease and velocity increase?

A

stenosis

140
Q

What can happen if there are 2 stenosis in series?

A

flow might stop completely!
- the first one slows it down
- second one stops it completely
=> this is the last thing we want in an artery, in the leg we call it physical ischemia

141
Q

what is a “bruit” in the context of cardiac sounds?

A

It is a vibration that one can hear just after a stenosis.

“sounds like a plane taking off”

142
Q

What is a “thrill “ in the context of cardiac auscultation?

A

A thrill is a vibration one can feel just after a stenosis

143
Q

What is a murmur?

A

If it’s a vibration across a heart valve (like a bruit, but valvular)

144
Q

What is the dichrotic notch?

A

It is the point at which the aortic valve shuts, causing a ery slight pressure increase, and then dicrotic limb cintinues (ie. descendant part of curve)
+ the dicrotic notch defines the transition between systole and diastole.

145
Q

How is pulse pressure defnied?

A

It is the difference between peak systolic pressure and the end diastolic pressure.
So when we measure BP with a sphygomanometer, pulse pressure is
systolic pressure - diastolic pressure
so most often, pulse pressure is 120mmHg - 80mmHg = 40mmHg

146
Q

What is mean arterial pressure and how is it calculated?

A

Mean arterial pressure can be estimated as:
diastolic pressure + 1/3 of pulse pressure
Therefore, most often, mean arterial pressure is 80+13mmHg = 93
If mean arterial pressure falls below 70mmHg, then organ perfusion is impaired

It is ALSO the area under the curve when looking at a pressure/time diagram of teh descending aorta

147
Q

Below which mean arterial pressure threshold is organ perfusion impaired?

A

70 mmHg

148
Q

What is the pulse?

A
  1. What we actually feel is a shock wave that arirves slightly before the blood itself
  2. the strength or what is also called the volume of the pulse is determined primarily by 2 things:
    a) The force with which the LV is able to eject blood .
    b) Pulse pressure the greater the oulse pressure, the stronger the pulse. a strong pulse is often described as “bounding”
149
Q

What can the causes of reduced pulse volume be? (3)

A
  1. LV failure
  2. Aortic valve stenosis
  3. Hypovolemia (dehydration, bleeding)
    such a pulse is often described as thready
150
Q

In which context is pulse pressure widened?

A

bradycardia

151
Q

Which non-pathological contexts can induce low peripheral resistance? (3)

A
  1. Hot bath
  2. Exercice
  3. Pregnancy - because have little boiler inside you producing heat so need to vasodilate to get rid of the heat
152
Q

How can low peripheral resistance induce a bounding pulse?

A

If peripheral resistance is low, then diastolic decline will be more quick, so blood will rush out into peripheral ciruclation, so diastolic pressure is lower, causing the bounding pulse.

153
Q

Why do we see a bounding pulse in patients with aortic incompetence?

A

In aortic incompetence, the aortic valve cannot close properly. So during diastole, some blood will flow back into the LV.
But because this blood is no longer in the aorta during diastole, then aortic diastolic pressure is lowered.
But if systolic pressure is the same and diastolic pressure is lower, then pulse pressure is LARGER.
And bounding pusle occurs wirth a larger pulse pressure

154
Q

What are the units of flow?

A

volume/time

155
Q

what are the units of velocity?

A

Distance/time

156
Q

What does stenosis do to proximal (ie. upstream) pressure?

A

increase

157
Q

What does stenosis do to distal (ie. downstream) flow and velocity?

A

Distal flow decreases with stenosis

Distal velocity increases with stenosis

158
Q

How does a stenosis create an aneurism?

A

The pressure proximally to the stenosis rises, and this can create the enlargement of the artery that we call an aneurism.

159
Q

Why can one not necessarily find a pulse when palpating an older person?

A

Part of the arterial tree calcifies with age, loses compliance and now cannot feel a pulse.

CVS (7 decks)

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