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Cardio Unit 2 > Week 6 - Cardiac Muscle Dysfunction And Failure Parts 1-3 > Flashcards

Week 6 - Cardiac Muscle Dysfunction And Failure Parts 1-3 Flashcards

1
Q

What is heart failure?

A

The inability of the heart to pump adequate amounts of blood through the circulation

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2
Q

What is the function of normal cardiac pump?

A

Pump blood from veins to arteries

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3
Q

How is BP created?

A

By volume of blood in vessels and the heart pumps out

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4
Q

Systolic pressure

A

Peak pressure generated

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5
Q

Diastolic pressure

A

Lowest pressure just before the next contraction

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6
Q

Mean arterial pressure (MAP)

A
  • Measure of BP over time
  • MAP = 1/3 x SBP + 2/3 x DBP
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7
Q

Total peripheral resistance (TPR)

A
  • Amount of force exerted against the circulating blood by the vasculature of the body
  • Affected by blood volume and resistance to flow in blood vessels
  • Less resistance, pump doesn’t have to work as hard to move the blood through the vessels
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8
Q

Pulse

A
  • Rhythmic dilation of an artery that results form beating of the heart
  • Norm: 72 bpm
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9
Q

Pulse pressure

A
  • Difference between systolic and diastolic blood pressure
  • Norm: 40 mm Hg
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10
Q

Afterload

A

Amount of pressure that the heart needs to exert to eject the blood during ventricular contraction

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11
Q

What does cardiac pumping increase?

A

Arterial pressure

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12
Q

TPR decreases at same time as pumping increases to prevent what?

A

Excessive pressure

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13
Q

What coordinates changes in TPR and cardiac pumping to regulate afterload?

A

Brain stem centers

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14
Q

Preload

A
  • Volume of blood received by the heart
  • Stretch, amount of volume being returned to the heart
  • Increase in preload will increase amount of blood returning to heart, which increases pumping force of heart by stretching it out more
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15
Q

What does greater pumping effectiveness do to venous pressure?

A

Decreases it
More blood is pushed out

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16
Q

How does the sympathetic nervous system maintain venous pressure and preload on the heart?

A

By constricting veins when pumping increasaes
Controls venous constriction and dilation of veins to maintain venous pressure

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17
Q

Afterload

A
  • Pressure or resistance the heart has to overcome to eject blood
  • Squeeze, the amount of resistance the heart has to overcome in order to eject blood
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18
Q

What do the differences in arterial and venous pressure drive?

A

Stroke volume and cardiac output
- CO = SV x HR

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19
Q

What causes blood to circulate with each beat?

A

Small decreases in venous pressure and large increases in arterial pressure

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20
Q

Ejection Fraction

A

% of blood in ventricle ejected into arteries
- Efficiency of cardiac pump (normally 50 or 50-70%
- EF = (EDV - ESV)/EDV
- Measures severity of HF

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21
Q

Stroke volume

A

Amount in mL ejected from the heart

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22
Q

Cardiac output

A

Amount of blood ejected/circulated in one minute

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23
Q

End systolic volume

A

Blood left in the ventricle after contraction

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24
Q

End diastolic volume

A

Amount of blood in ventricle just before contraction

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25
Q

What is CHF

A
  • Heart is failing to do its job: pumping blood from the veins to the arteries
  • Cardiac output is not maintained
  • Arterial pressure may not rise enough w/ each contraction or venous pressure may become too high
  • EF typically low in HF - used to determine severity
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26
Q

At what percentage of ejection fraction do issues start occurring with HF?

A

41-49%

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27
Q

What percentage of ejection fraction causes significantly impaired function in HF?

A

< or equal to 40

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28
Q

How do the two pumps in the heart work in series?

A

They fill and empty each other

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29
Q

Pulmonary circulation has tremendous branching, low resistance and pressure, what does this result in?

A

Less work for right ventricle

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30
Q

Left pumps throughout the body

A
  • Tremendous difference in resistance among vascular beds
  • Much higher overall resistance than pulmonary
  • Results in much more work for left ventricle
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31
Q

Function reflected in anatomy - left ventricle

A
  • Basically a thick cone pumping against a high pressure
  • Has a much greater oxygen consumption than the right due to more muscle and pumps harder
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32
Q

Function reflected in anatomy - right ventricle

A

Basically a thin flap pumping against a very low pressure

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33
Q

Which side of the heart is most likely to fail first?

A
  • Left side unless there’s an injury to the R side
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34
Q

Compensated cardiac output

A

When cardiac output is balanced regardless of demand on the heart

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35
Q

Decompensated cardiac output

A

If cardiac output is not balance, or cannot keep up with demand

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36
Q

What happens if right and left-sided cardiac output are not identical over a small time frame?

A

One side will become backed-up (congested) and the other will have low pressure
- Pulmonary backed up and systemic low pressure
OR
- Systemic backed up and pulmonary low pressure

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37
Q

How does the autonomic nervous system adjust to allow us to exercise?

A

Greater CO per EDV

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38
Q

True or false: ANS adjustments may allow high level of activity with CHF

A

False

ANS adjustments may allow LOW level activity with CHF

39
Q

What happens with further decline in contractility?

A
  • Does not allow activity
  • Leads to death
40
Q

How is cardiac output maintained?

A

By compensations

41
Q

What does lack of compensation (decompensation) lead to?

A
  • Too much fluid in the central or pulmonary veins
  • Too much blood volume in the heart chambers
  • Insufficient cardiac output
42
Q

Hypertension

A
  • Increased arterial pressure leads to L ventricular hypertrophy
  • Leads to overstretched contractile fibers and less effective pump
43
Q

Medical management of hypertension

A

ACE inhibitors
Calcium channel blockers
Diuretics
Beta blockers

44
Q

What is coronary artery disease (myocardial infarction/ischemia) related to?

A

Dysfunction of the left or right ventricle - or both - as a result of injury

45
Q

What can cardiac muscle dysfunction cause?

A

Coordination issues

46
Q

What can cardiac arrhythmias impair?

A

Rapid or slow arrhythmias can impair functioning of left and/or right ventricle

47
Q

Muscle as a cause of poor cardiac performance

A
  • Weakness due to myocarditis, MI or cardiomyopathy
  • Partial wall damage from ischemia or infarct
48
Q

Dyskinesia

A

Uncoordinated - after MI, if conduction is compromised and one ventricle moves later than the others

49
Q

Decreased wall movement

A

Hypokinesia: decreased movement
Akinesia: localized are of no movement

50
Q

Abnormal conduction

A

Decreases coordination of contraction

51
Q

Abnormal automaticity

A

Pacemaker not regular
- Tachycardia or bradycardia
- Multiple areas of automaticity at once (fibrillation)

52
Q

Stenosis

A

Can’t open enough so not enough blood can get out

53
Q

Aortic stenosis

A

Tight aortic valve so not enough blood can get through - problem sending enough blood and oxygen to tissues of the body

54
Q

Regurgitation

A
  • Incompetent
  • Doesn’t close properly, can’t close all the way - can cause back leak of blood
55
Q

Mitral regurgitation

A

Mitral valve is floppy - blood is going to get backed up to the lungs

56
Q

Heart valve abnormalities

A
  • Blocked/stenotic valve or incompetent/regurgitant valves cause heart muscle to contract more forcefully
  • Associated with myocardial dilation and hypertrophy
  • Surgeries: valve replacement and valvuloplasty
57
Q

What kinds of valve replacements can occur?

A
  • Procine valve (open heart surgery)
  • Metallic valve (open heart surgery)
  • TAVR (minimally invasive)
58
Q

Cardiomyopathy

A

Contraction and relaxation of myocardial muscle fibers are impaired

59
Q

Primary cause of cardiomyopathy

A

Problems with conduction and infection

60
Q

Secondary causes of cardiomyopathy

A

Diabetes, autoimmune disorders, alcohol, heavy metal or drug toxicity
- More common

61
Q

Blockage/Compression of Vessels/Chambers

A
  • Pulmonary (or other) embolus
  • Valsalva collapsing vena cavae
  • Accumulation of fluid in pericardium compressing R ventricle — cause heart failure
  • Tumors blocking heart chambers or compressing vessels
62
Q

Saddle pulmonary embolus

A

Result in total or near blockage of pulmonary arteries —> no pulmonary blood flow —> no filling of L ventricle —> no output of L ventricle —> rapid onset of dyspnea, LOC, death

63
Q

Hemopericardium

A
  • Pressure inside pericardium prevents filling of R ventricle (cardiac tamponade)
  • Decrease in pulmonary blood flow can be life threatening
  • L ventricle cannot be filled
  • Same consequences as saddle embolus, develops more gradually
  • Drain pericardium to relieve pressure (pericardiocentesis)
64
Q

NYHA Class I

A
  • Mild
  • No limitation is experienced in any activites
  • No symptoms from ordinary activities
65
Q

NYHA Class II

A
  • Slight, mild limitation of activity
  • Patient is comfortable at rest or with mild exertion
66
Q

NYHA Class III

A
  • Marked limitation of any activity
  • Patient only comfortable at rest
67
Q

NYHA Class IV

A
  • Most severe
  • Any physical activity causes discomfort
  • Symptoms present at rest
68
Q

Common signs of CHF

A
  • R sided elevated jugular venous pressure
  • Hepatojugular reflex
  • Third heart sound
  • Bilateral pulmonary wheezes
  • Retention of excessive body fluid
  • Peripheral edema
  • Weight gain
69
Q

Common symptoms of CHF of the inability to compensate

A

Fatigue
Dyspnea on exertion
Decreased exercise tolerance

70
Q

Common symptoms of CHF due to fluid backup in the pulmonary system

A

Paroxysmal nocturnal dyspnea
Orthopnea

71
Q

Orthopnea

A

Inability to sleep unless partially upright
Quantified by number of pillows used to allow one to sleep

72
Q

Cyanosis

A

Due to lack of perfusion to the tissues

73
Q

Chronic heart failure

A

Long-term problem with many of the symptoms described

74
Q

Signs and symptoms of chronic heart failure depend on what?

A

Left vs. right
Forward vs. backward
Systolic vs. diastolic

75
Q

Acute heart failure

A
  • Life threatening condition
  • Results in Cardiogenic shock and death w/o intervention
  • Catastrophic loss of one-way valve system or other structural integrity
  • Perforation, blockage by foreign object or tumor, poisoning of cardiac muscle
  • Serious arrhythmias: V-fib, V-tach
76
Q

Left sided acute heart failure

A

Rupture of aorta, blow out of aortic valve

77
Q

Right sided acute heart failure

A

Blockage by saddle embolus or hemopericardium

78
Q

Right-sided heart failure

A
  • Results of failing to empty vena cave
  • Jugular distention
  • Systemic congestion
  • Dependent edema
  • Sacral edema and ascites
  • Nocturia as fluid is displaced from LEs to thorax while asleep
  • Congestion of liver and spleen
  • Impaired liver function and immunity: further edema and decreased blood clotting
79
Q

Left sided HF

A

Results from failure of LV to empty pulmonary veins and fill systemic arteries

80
Q

What does congestion of pulmonary veins and capillaries cause in left sided HF

A
  • Dyspnea
  • Orthopnea
  • Paroxysmal nocturnal dyspnea
81
Q

What does low cardiac output cause in left sided heart failure

A

Symptoms of decreased cerebral perfusion
Cool extremities may progress to rubor of dependency and to cyanosis

82
Q

What is the most common cause of RHF?

A

LHF because it usually starts first

83
Q

Interaction of RHF and LHF

A

Low systemic cardiac output causes fluid retention by kidneys - excess fluid increased preload on R side
Congestion of pulmonary circulation increased afterload on R ventricle

84
Q

Forward heart failure

A

Problems primarily due to low cardiac output
Ischemic injury in tissues
Cool, cyanotic extremities and face

85
Q

Backward heart failure

A

Problems primarily due to venous congestion
Increased venous pressure w/ leakage of fluid from capillaries
Pulmonary edema with LHF
Peripheral edema with RHF

86
Q

1+ Pitting edema

A

Not obvious w/o checking
About 2 mm pit
Pit lasts a few seconds

87
Q

2+ pitting edema

A

Obvious to trained person
About 4mm pit
Pit lasts several seconds

88
Q

3+ pitting edema

A

Obvious to eye
About 6 mm put
Pit lasts a few minutes

89
Q

4+ pitting edema

A

Grossly distorted limb
“Sausage fingers or toes”
About 8 mm pit
Pit lasts several minutes

90
Q

Systolic failure

A

Insufficient myocardial muscle strength relative to conditions to pump the blood throughout the body
Signs and symptoms of heart failure more likely to be experienced

91
Q

Diastolic failure

A

Insufficient filling/low SV
May not be noticeable except during heavier exertion
Ventricle(s) too stiff to allow sufficient filling
May lead to sudden onset of tachycardia, arrhythmias and flash pulmonary edema

92
Q

Mean arterial pressure

A

Often used to monitor perfusion of organs
MAP = CO x TPR
Normal ranges from 65 to 110 mmHg

93
Q

Common causes of decompensation

A

Superimposed illness like pneumonia
Myocardial infarction
Arrhythmia
Uncontrolled HTN
Failure to comply with treatment
Excessive fluid or salt intake
Anemia, thyrotoxicosis, other problems that increase myocardial work

Cardio Unit 2 (13 decks)

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