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Lindsays Flashcardlet > RE CH23 > Flashcards

RE CH23 Flashcards

0
Q

Pressure in the pericardial cavity may increase how much before symptoms of cardiac to tamponade occurs?

A

10-fold

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1
Q

The space between the visceral pericardium and parietal pericardium is known as the _______ cavity and contains how much fluid?

A

Pericardial cavity contains 10-25 mL of fluid

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2
Q

Where does the right atrium receive blood from?

A

Superior vena cava, inferior vena cava, & coronary sinus

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3
Q

The atrial kick that the LV receives from the LA is increases LVEDV by how much?

A

20-30%

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4
Q

Why does the left ventricle have more muscle mass compared to the right?

A

It must overcome SVR or Afterload to maintain cardiac output

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5
Q

Why are the three layers of the myocardium?

A
  • Epicardium (mesothelium, connective tissue, fat)
  • Myocardium (muscle)
  • Endocardium (endothelium and connective tissue)
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6
Q

What is the normal tricuspid valve area? What area size is associated with symptomatic tricuspid stenosis

A

Normal: 7 cm²

Symptomatic TS: 1.5 cm²

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7
Q

What is the normal mitral valve size? What size is associated with symptomatic mitral stenosis?

A

Normal: 4-6 cm²

Symptomatic MS: area is decreased by 1/2 (2-3 cm²)

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8
Q

What is the normal aortic valve area? What size is associated with symptomatic AS?

A

Normal: 2.5 - 3.5 cm²

Symptomatic AS: reduction by 1/3 to 1/2

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9
Q

What does the left main coronary artery branch into?

A

LAD and circumflex

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10
Q

What does the LAD perfuse?

A
  • Anterior 2/3 of the interventricular septum
  • right and left bundle branches
  • anterior & posterior MV papillary muscles
  • anterior lateral & apical walls of LV
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11
Q

What does the circumflex perfuse?

A
  • left atrium
  • posterior and lateral LV
  • Anterolateral papillary muscle
  • AV node in 10% of population
  • SA node in 45% of population
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12
Q

What does the right coronary artery perfuse?

A
  • SA and AV nodes
  • RA and RV
  • posterior 1/3 of the interventricular septum
  • left bundle branch
  • interatrial septum
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13
Q

What is coronary artery dominance?

A

Which coronary artery provides blood flow to the PDA

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14
Q

What percent of the population is:

  • right coronary artery dominant
  • left coronary artery dominant
  • mixed dominance
A
  • Right coronary artery dominant: 50%
  • Left coronary artery dominant: 10-15%
  • Mixed: 35-40%
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15
Q

What percent of blood does the coronary sinus collect from the LV?

A

85%

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16
Q

Bachman’s bundle (Anterior intermodal tract) sends impulses from the SA node to where

A

LA and then travels down the atrial septum to the AV node

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17
Q

The wenckebach tract (middle internodal tract) sends impulses from the SA node to where?

A

Curves behind the SVC before descending to the AV node.

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18
Q

The Thorel tract (posterior internodal tract) sends impulses from the SA node to where?

A

Along the terminal crest to the atrial septum and then to the AV node.

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19
Q

What inhibits interaction of actin and myosin in the myocardium?

A

Troponin-tropomyosin complex

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20
Q

What occurs during phase 0 of the myocardial action potential?

A

Rapid depolarization of cardiac muscle due to opening of fast sodium channels and inward Na+ movement

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21
Q

What occurs during phase 1 of the myocardial action potential?

A

Early repolarization due to transient potassium permeability and outward potassium movement

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22
Q

What occurs during phase 2 of the myocardial action potential?

A

Prolonged (plateau) depolarization. Due to delayed opening of slow (L-type) Ca++ channels and inward calcium movement. Membrane permeability of potassium is greatly reduced

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23
Q

What occurs during phase 3 of the myocardium action potentials got

A

Depolarization. The slow calcium channels close near the end of the action potential and potassium permeability is restored and toward potassium current restores the resting potential.

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24
Q

What is threshold potential?

A

Where the action potential can fire. Between -70 and -65 MV

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25
Q

What is the absolute refractory period?

A
  • The time during which a connected action potential may not be evoked.
  • Occurs from phase 0 until middle of phase 3, when the membrane drops below -60 mV
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26
Q

What is the relative refractory period?

A
  • The time during the action potential when a second stimulus can result only with an action potential with decreased amplitude, upstroke velocity, and conduction velocity.
  • occurs during middle of phase 3 to beginning of phase 4, when the membrane potential ranges from -60 to -90 mV
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27
Q

What is the resting potential of the myocardium?

A

-90 mV

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28
Q

What is the resting potential of the SA node action potential?

A

-55 to -60 mV (closer to threshold potential)

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29
Q

Why is the resting membrane potential of the SA node higher than the myocardium?

A

The SA node membrane is more permeable to sodium.

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30
Q

What phases occur in the SA node action potential

A

Phase 4, phase 0, and phase 3

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31
Q

What is the intrinsic firing rate of the AV node and ventricular cells?

A

AV node: 40-60 beats/min

Ventricular cells: 15-30 beats/min

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32
Q

At rest how much of the cardiac output passes through the coronary vasculature? This equates to ______ mL/min

A

4-5% of the cardiac output

225 mL/min

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33
Q

What factors determine coronary artery oxygen supply?

A

Coronary artery anatomy, diastolic pressure, diastolic time, O2 extraction (Hb& Sao2)

34
Q

What factors determine coronary artery oxygen demand

A

Heart rate, preload, afterload, & contractility

35
Q 
Which factor most negatively impacts MvO2?
A. Heart rate
B. Pressure work
C. Contractility
D. Wall stress
A

A. Heart rate

Doubling the number heart rate doubles the MVO2

36
Q

What percent of coronary filling and myocardial perfusion occurs during diastole?

A

80-90%

37
Q

What is the MAP range for coronary autoregulation?

A

60-140 mmHg

38
Q

What is the equation to estimate coronary perfusion pressure?

A

CPP= DBP - LVEDP

39
Q

Is DBP or LVEDP the primary determinant for CPP?

A

DPB, because normal (80mmHg) is significantly greater than normal LVEDP (10mmHg)

40
Q

What is the difference between cardiac output and cardiac index?

A

Cardiac output is the amount of blood ejected from the LV in 1 minute whereas the cardiac index is the CO/BSA

41
Q

What is the average cardiac output and cardiac index?

A

CO: 5L/min

CI: 2.5 L/min

42
Q

How is cardiac output calculated?

A

HR x SV

43
Q

What factors affect stroke volume?

A

Preload, Afterload, Contractility

44
Q

What is the Frank Starling law of the heart?

A

The greater the wall tension (preload) the greater the compensatory increase in myocardial contractility

45
Q

How do we measure preload in the clinical setting?

A

PAOP or pulmonary artery diastolic pressure.

46
Q

How do we measure Afterload in the clinical setting?

A

SVR

47
Q

What is the equation to determine SVR

A

SRV = 80 x (MAP - CVP)/CO

48
Q

What is a normal SVR value?

A

800 - 1500 dyn.s/cm^5

49
Q

How is EF calculated?

A

EF = (EDV - ESV)/EDV x 100

50
Q

Which diagnostic tool is considered the gold standard for assessing Intraoperative myocardial performance?

A

TEE

51
Q

What is the baroreceptor reflex?

A

Hypertension stimulates baroreceptors that sends afferent response via hearing and glossopharyngeal nerves. Aortic baroreceptors send an afferent response via the vagus nerve that decreases HR, Contractility and causes vasodilation.

52
Q

What is the valsalva maneuver?

A

Forced exhalation against a closed glottis causes baroreceptor reflex.

53
Q

What is Cushing’s reflex?

A

Increased intracranial pressure resulting in cerebral edema causes SNS response to increase BP

54
Q

What is the chemoreceptors reflex?

A

Decreased O2 saturation and increased CO2/H+ ion concentration causes increased respiratory drive and increased BP (same neural pathway as baroreceptor reflex)

55
Q

What is the oculocardiac reflex?

A

Traction on the extra ocular muscles/pressure on the globe causes afferent reponse via Trigeminal nerve (V) and efferent response via the vagal nerve (X) causing bradycardia, hypotension, and arrhythmias
** think five and dime for neural pathway

56
Q

What is the celiac reflex?

A

Traction on the structures within the abdominal and thoracic cavities causes vagal stimulation leading to bradycardia, hypotension, and apnea.

57
Q

The venous system contains ____% of the blood volume whereas the arterial system contains _____% of the blood volume.

A

Venous system: 60%

Arterial system: 20%

58
Q

What are the first branches off of the ascending aorta?

A

Right and left coronary arteries.

59
Q

What are the three major branches off of the thoracic aorta?

A

Brachiocephalic (innominate), left common carotid, left subclavian.

60
Q

What is a normal PVR value?

A

50 - 150 dyne/sec/cm^5

61
Q 
Which of the following is the most efficient in responding to rapid changes in blood pressure?
A. Chemoreceptors
B. Baroreceptors
C. Atrial stretch reflex
D. Hormonal response
A

B. Baroreceptors

62
Q

Between which range of MAP do baroreceptors transmit impulses to the inhibitory centers of the vasomotor center?

A

60-180 mmHg

63
Q

Where is the cardiovascular (vasomotor) center located in the brain?

A

The medulla and pons

64
Q

What do chemoreceptors primarily respond to?

A

Changes in PaO2

65
Q

What is the most potent vasoconstrictive substance secreted by the body?

A

Angiotension II

66
Q 
The risk of cardiac disease doubles with increment of what pressure above 115/75?
A. 10/5
B. 15/10
C. 20/10
D. 25/15
A

C. 20/10

67
Q

What are the Hemodynamic goals for patients with coronary artery disease? Preload, Afterload, Contractility, HR, rhythm

A 
Preload: decrease/maintain
Afterload: Maintain
Contractility: decrease/maintain
Heart rate: slow
Heart rhythm: NSR
68
Q

What is Beck’s Triad that is associated with cardiac tamponade?

A

Hypotension, jugular vein dissension, and distant muffled heart sounds.

69
Q

What are hemodynamic goals of cardiac tamponade for preload, Afterload, Contractility, heart rate, heart rhythm?

A 
Preload: maintain or increase
Afterload: maintain
Contractility: maintain or increase
Heart Rate: maintain
Heart rhythm: NSR
70
Q

What is the normal mitral valve area? Symptoms of mitral stenosis at rest occur when the area decreases to what?

A

Normal: 4-6 cm²

Symptomatic MS: <1cm²

71
Q

In mitral stenosis what are the hemodynamic goals for the following:

  • Heart rate
  • Afterload
  • PVR
  • Preload
A
  • Heart rate: Low normal
  • Afterload: Normal
  • PVR: Avoid increases
  • Preload: Normal to increased
72
Q

Does pulmonary capillary wedge pressure under or overestimate LVEDP?

A

Overestimates

73
Q

What 4 things determine the regurgitant fraction in mitral regurgitation?

A
  1. Size of regurgitant valve orifice
  2. Pressure gradient between LA and LV
  3. Time available for regurgitation (systole)
  4. Aortic outflow impedance SVR
74
Q

_________(eccentric/concentric) hypertrophy of the LV occurs with chronic mitral regurgitation

A

Eccentric hypertrophy (LV chamber dilation)

75
Q

What is founds on the PCWP tracing with acute mitral regurgitation?

A

Pathologic V wave

76
Q

What are the hemodynamic goals for mitral regurgitation for:

  • Heart rate
  • Afterload
  • PVR
  • Preload
A
  • HR: Increased
  • Afterload: Decreased
  • PVR: Avoid increases
  • Preload: Normal to increased
77
Q

What is the normal aortic valve area?

A

2.5-3.5 cm²

78
Q

An aortic valve area of less than _____cm² is associated with severe AS and a valve area of less than _____cm² is associated with sudden death.

A

Severe AS: <1cm²

Sudden death: <0.7cm²

79
Q

__________(concentric/eccentric) left ventricular hypertrophy occurs with aortic stenosis.

A

Concentric (wall thickening)

80
Q

What are the hemodynamic goals of aortic stenosis:

  • HR
  • Afterload
  • PVR
  • Preload
A
  • HR: Normal to Slow
  • Afterload: maintain to slight increases
  • PVR: maintain
  • Preload: Increased
81
Q

What are the hemodynamic goals for aortic regurgitation:

  • HR
  • Afterload
  • PVR
  • Preload
A
  • HR: Moderate increase
  • Afterload: Decrease
  • PVR: Maintain
  • Preload: normal to increased
82
Q

What phases of the myocardial cell action potential does lidocaine affect

A

Phase 0 - inhibitory effect by decreasing sodium influx

Phase 4 - lengthens duration by decreasing permeability to potassium

83
Q

What phases of the myocardial cell action potential do calcium channel blockers affect?

A

Phase 2

Lindsays Flashcardlet (27 decks)

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