Cardiac Physiology Flashcards

1
Q

What is the primary determinant of myocardial oxygen consumption?

A

Heart rate

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2
Q

How much oxygen does the heart extract?

A

75-80%

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3
Q

What valve corresponds with the beginning of the R wave?

A

Closing of the mitral valve

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4
Q

What corresponds with the end of the QRS?

A

Opening of the aortic valve

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5
Q

What corresponds with the end of the T wave?

A

Closure of the aortic valve

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6
Q

What does mild aortic stenosis also suggest?

A

Diastolic dysfunction

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7
Q

What cardiac output dependent on in someone with diastolic dysfunction?

A

LV filling during diastole

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8
Q

What does LV filling depend on?

A

Proper atrial ejection (only happens in normal sinus rhythm)

Enough time to fill (HR control)

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9
Q

Assuming normal cardiac function, what is the relationship of partial pressures of inhaled anesthetics at equilibrium in the CNS, blood and alveoli?

A

Pcns=Pblood = Palveoli

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10
Q

What are the sympathetic cardiac innervations?

A

Alpha 1
Beta 1
Beta 2

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11
Q

What do the sympathetic fibers travel through?

A

The stellate ganglions

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12
Q

Which side has a greater effect on heart rate?

A

The right stellate

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13
Q

Which. Stellate ganglia has more effect on MAP and contractility

A

Left

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14
Q

What does beta 2 do in the heart?

A

Positive chronotropy > inotropy

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15
Q

What does alpha 1 do in the heart?

A

Positive inotropy

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16
Q

What are the sympathetic cardiac innervations?

A

Alpha 1
Beta 1
Beta 2

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17
Q

What do the sympathetic fibers travel through?

A

The stellate ganglions

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18
Q

Which side has a greater effect on heart rate?

A

The right stellate

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19
Q

Which. Stellate ganglia has more effect on MAP and contractility

A

Left

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20
Q

What does beta 2 do in the heart?

A

Positive chronotropy > inotropy

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21
Q

What does alpha 1 do in the heart?

A

Positive inotropy

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22
Q

What is phase 0 of the ventricular contraction?

A

Fast sodium influx

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23
Q

What is phase 1?

A

Inactivation of sodium channels

Transient leak of potassium out (partial repolarization)

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24
Q

What is phase 2?

A

The plateau where L type calcium channels open to release calcium from the sarcoplasmic reticulum

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25
Q

What is phase 3?

A

Complete repolarization by efflux of potassium by voltage gated K channel and calcium activated channels.

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26
Q

What is phase 4?

A

The resting phase maintained by K

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27
Q

What happens to the heart in hypocalcemia?

A

Less calcium is available for release so you get a slower repolarization time (wider QRS and prolonged QT)

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28
Q

What is the second messenger in cardiac myocytes?

A

IP3 which stimulates the release of cytoplasmic calcium which in turn activates the ryanodine receptors on the sarcoplasmic reticulum

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29
Q

What is the second messenger in cardiac myocytes?

A

IP3 which stimulates the release of cytoplasmic calcium which in turn activates the ryanodine receptors on the sarcoplasmic reticulum

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30
Q

What do T wave inversions in the precordial leads indicate?

A

Severe right heart dysfunction (PE)

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31
Q

Where do thebesian veins empty?

A

Into the left heart

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32
Q

What are the most common cardiac benign tumors in adults and where are they found?

A

Myxoma

Found in the left atrium and inter atrial septum

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33
Q

Where does RCC Mets usually end up in the heart?

A

Right atrium and IVC

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34
Q

What is normal PCWP?

A

6-12 mm Hg

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35
Q

What is a normal CI?

A

2.5-4L/min/m2

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36
Q

What is normal SVR?

A

800-1200 dynes X sec/cm 5

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37
Q

What is resynchronization therapy

A

Biventricular packng where the pacer wires are in the right atrium, right ventricle and coronary sinus (activates the left ventricle)

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38
Q

What does unipolar pacemaking require?

A

Farther distance for current to travel so a large stimulus artifact can be seen on ECG

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39
Q

What may happen with unipolar pacemakers?

A

Other excitable tissue may be stimulated due to the large current required

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40
Q

What is pulses paradoxus?

A

A decrease greater than 10 mmHg in systemic blood pressure during inspiration characteristic of cardiac tamponade

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41
Q

Why does pulses paradoxus occur?

A

Due to ventricular interdependence

When the right heart fills during pericardial tamponade the ventricle can’t distend to accommodate the volume so the septum bulges into the left ventricle decreasing SV and therefor systemic blood pressure by more than 10 mmHg

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42
Q

When is right atrial collapse seen in tamponade?

A

In late diastole

Early systole

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43
Q

When does RV collapse occur in tamponade?

A

In early diastole

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44
Q

How long since a patient had an MI should they have elective surgery delayed?

A

1 month

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45
Q

What ECG lead is most sensitive for MI?

A

Lead V

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46
Q

Where is lead V placed?

A

The anterior axillary line of the 5th intercostal space

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47
Q

What is lead II sensitive for?

A

P wave characteristics

Arrhythmias

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48
Q

What is the most common causes of MI?

A

Plaque ruptures

Oxygen supply imbalance

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49
Q

What is the most common cause of intraoperative MI

A

Oxygen supply imbalance

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50
Q

How much air entrainment does it take for a fatal air lock situation?

A

3-5 ml/kg

10-15 ml/kg of CO2

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51
Q

What does the RCA supply?

A
Inferior wall of the LV 
lateral and posterior walls of RV
1/3 of inter ventricular septum + posteromedial papillary muscle (PDA) in 85% of people
AV node 
SA node (60%)
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52
Q

What does it mean if someone has a left dominant coronary system?

A

In 15%, the PDA comes off the LCX. This is left dominant

PDA gives off AV nodal artery

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53
Q

What does the LAD supply?

A

The anterior wall of heart
Inter ventricular septum
Bundle branches and Purlinje system

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54
Q

What does LCX supply?

A

The posterior and lateral walls of the LV

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55
Q

What do you do in unstable Torsades?

A

Unsynchronized cardioversion

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56
Q

What would be first line measures in a hypotension patient with HOCM?

A

Increase preload

Avoid inotropes and vasodilation

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57
Q

What cautery should be used with an active AICD?

A

Bipolar and short bursts

Also, place dispersive pad near the surgical field

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58
Q

What happens to an AICD with a magnet?

A

It will disable the anti-tachy arrhythmia therapy

- must interrogate after surgery!

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59
Q

What increases UOP in CPB?

A

Mannitol in the priming solution
Pulsation perfusion
Maintaining MAP

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60
Q

What are the whole blood concentration of heparin sufficient for CPB?

A

3-4 U/ml

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61
Q

What is a normal ACT?

A

110-140 seconds

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62
Q

What is adequate ACT for CPB?

A

400-480 seconds

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63
Q

What factors decrease the reliability of an ACT?

A

Hypothermia

Hemo dilution

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64
Q

Who is resistant to heparin?

A

Those with anti thrombin 3 deficiency

Those who have had 2-4 units of FFP

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65
Q

What does cardioplegic solution do to the resting membrane potential of the cardiac myocytes?

A

Makes it more positive and makes cells depolarize
After depolarization, the potassium rich solution establishes a new resting value that is less negative than before so cells cannot fully repolarize. This inactivates voltage gated sodium channels

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66
Q

What phase does cardioplegic arrest the heart in?

A

Diastole

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67
Q

What does blood based cardioplegic solution do?

A

Enhances oxygen carrying capacity and free radical scavenging so enhanced recovery of ventricular function and less periop MIs

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68
Q

How much does myocardial oxygen consumption decrease by with hypothermia?

A

50% for every 10 degrees

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69
Q

What else does hypothermic cardioplegic solution do?

A

Increases the time the myocardium can tolerate ischemia

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70
Q

What are the adverse effects of hypothermia?

A
Myocardial edema
Phrenic nerve injury
Citrate toxicity
Impaired oxygen dissociation 
Increased plasma viscosity 
Decreased RBC formability
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71
Q

What has been shown about warm cardioplegic

A

Less atrial fib, use of balloon pump, low CO syndrome, periop MI

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72
Q

What is retrograde cardioplegia?

A

Placing a balloon tipped catheter in the coronary sinus

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73
Q

What is ante grade cardioplegia?

A

Putting it in between the aortic cannula and the aortic valve OR
putting it in the coronary ostia

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74
Q

In what conditions may retrograde cardioplegia need to be used?

A

Aortic insufficiency
AV surgery
Severely stenosis coronary arteries

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75
Q

What is the drawback of retrograde cardioplegia?

A

Inadequate delivery to the free wall of the RV and posterior third of the septum

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76
Q

What is the resting membrane potential of a normal cardiac myocyte?

A

-90mV

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77
Q

What is the resting membrane potential of a cardioplegic cardiac myocyte?

A

-60 mV

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78
Q

What is McConnell’s sign on TEE?

A

RV mid-free wall akinesia with spared apex

Finding of PE

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79
Q

What are some TEE findings of pulmonary embolism?

A

Dilated coronary sinus, right atrium, hepatic veins, RV, tricuspid regurg, bulging/flattening of septum

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80
Q

What is a type III protamine reaction?

A

Pulmonary HTN + RV FAILURE mediated by heparin-protamine complexes and TXA2

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81
Q

What is a type I protamine reaction?

A

Direct histamine or nitric oxide release

Happens with rapid administration

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82
Q

What is a type II protamine reaction?

A

IgE mediated anaphylaxis

A - true anaphylaxis
B- immediate anaphylactoid reaction
C - delayed anaphylactoid reaction

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83
Q

What patients may be at increased risk for type II protamine reaction?

A

Diabetics taking NPH
Fin fish allergy
Prior protamine exposure

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84
Q

What is the treatment for type III protamine reaction?

A
Cessation of protamine infusion
Reinstate CPB
Intropes (milrinone, isoproterenol)
Nitric oxide for the Pulm HTN 
Small dose of heparin to reduce the heparin-protamine complex sizes
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85
Q

What does fenoldopam do?

A

Increases renal and splanchnic blood flow
Decreases peripheral vascular resistance
Diuresis and natriuresis
Increase intraocular

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86
Q

What are the contraindications to IABP?

A
Aortic regurgitation
Aortic dissection
Aortic stent
Aortic aneurysm
Severe bilateral PVD 
Aortic or Ilio-femoral bypass grafts 
Tachyarrythmias 
Uncontrolled sepsis
Uncontrolled bleeding
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87
Q

What are the indications for IABP?

A

Improved coronary perfusion (increases diastolic pressure, decreases afterload)

Cardiogenic  shock
Refractory ventricular arrhythmias 
Refractory unstable angina
Decompensated systolic heart failure
Cardio support for procedure
Decompensated aortic stenosis
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88
Q

How does IABP work?

A

It inflates during diastole and deflates right before systole so it augments diastolic pressure and therefore coronary perfusion pressure and decreases afterload

This decreases myocardial workload and oxygen consumption

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89
Q

When should the IABP be deflated on ECG.

A

At the peak of the R wave which signals the start of systole

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90
Q

When should the balloon inflate?

A

The start of diastole, so the middle of the T wave (right after closure of the aortic valve)

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91
Q

Who should get antibiotic prophylaxis?

A
  1. Prosthetic valves
  2. Previous endocarditis
  3. Palliative shunts and conduits
  4. Unrepaired cyanotic heart lesions
  5. Repaired congenital heart problems with residual defects
  6. Cardiac transplant with valvular disease
  7. Respiratory tract procedures that break the mucosa
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92
Q

What are the absolute contraindications to TEE probe placement?

A
Esophageal webs/strictures
Esophageal tumor 
Scleroderma
Malloryl-Weiss tear
Zenker diverticulum
Recent esophageal variceal bleeding
Active upper GI bleeding 
Recent upper GI surgery 
Esophagectomy
Perforated viscus
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93
Q

What is the medication of choice to prevent arrhythmia in patients with prolonged QT?

A

Beta blockers

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94
Q

What is the treatment for patients with prolonged QT that are refractory to medication?

A

Pacemakers

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95
Q

How long of a QT is an indication for an ICD.

A

Greater than 550

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96
Q

Why are centrifugal pumps preferred over roller pumps?

A

Less blood destruction, lower risk of air emboli, lower line pressures, elimination of wear and spallation

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97
Q

What is Beck’s triad?

A

Hypotension
Increased venous pressure
Muffled heart sounds

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98
Q

What should you use to induce someone with pericardial tamponade?

A

Etomidate or ketamine

Must maintain SVR and sympathetic stimulation

99
Q

Why might you do an awake intubation for pericardial tamponade?

A

To improve venous return to the heart by avoiding induction drugs and positive pressure ventilation

100
Q

Which papillary muscle is more likely to rupture and why?

A

Posteromedial papillary due to the single blood supply (RCA or LCX)

101
Q

What supplies the anterolateral papillary muscle?

A

LAD and LCX

102
Q

Where do you see air emboli most often in CPB?

A

RCA due to its superior orientation when the patient is supine

103
Q

How can you treat protamine induced hypertension?

A

Milrinone
Epinephrine
Nitroglycerin

104
Q

What is vasoplegia syndrome?

A

Decreased SVR (<1600), Resistance to vasopressors , High cardiac output (2.5) within the first 4 postop hours

105
Q

What are the treatments for vasoplegia syndrome?

A

Methylene blue

Vasopressin

106
Q

What mediates type III protamine reactions?

A

Thromboxane A2

- released from platelets and macrophages stimulated by protamine-heparin complexes

107
Q

What is type II protamine reactions mediated by?

A

IgE - anaphylactic reaction

108
Q

What mediates type I protamine reaction ?

A

Histamine

109
Q

What is the a wave on CVP tracing?

A

Atrial contraction

110
Q

What is the c wave on CVP tracing?

A

Tricuspid valve bulging into the right atrium during RV isovolumic contraction

111
Q

What is the X descent in CVP tracing?

A

Tricuspid valve descends in the RV with ventricular ejection

112
Q

What is the V wave on CVP tracing?

A

Venous return to the right atrium

113
Q

What is y descent?

A

Atrial emptying in the RV through the open tricuspid

114
Q

What is a “cannon a wave”?

A

A large a wave without the c wave

115
Q

What does a cannon a wave mean?

A

AV dissociation - atrium is contracting against a closed triscuspid valve

116
Q

What would CVP tracing look like with atrial fibrillation?

A

No “a” wave

117
Q

What would CVP tracing look like in tricuspid regurg?

A

Tall c and v waves

Loss of X descent

118
Q

What would tricuspid stenosis look like?

A

Tall a wave
Tall v wave
Loss of y descent

119
Q

What would RV ischemia look like in CVP tracing?

A

Tall a and v waves
Steep X and y descent
M or W configuration

120
Q

What would pericardial constriction look like in CVP tracing?

A

Tall a and v waves
Steep X and y descent
M or W configuration

121
Q

What would cardiac tamponade look like on CVP tracing?

A

Dominant X descent, minimal y descent

122
Q

What intervention should be done if a patient is found to have severe CAD but needs operation within 14 days and there is a high risk of bleeding?

A

Balloon angioplasty

123
Q

What intervention should be done if a patient is found to have severe CAD but needs operation within a few weeks and there is a high risk of bleeding?

A

Bare metal stent placement and dual anti-platelet therapy for 4-6 weeks
Continue ASA only in the perioperative period if 30 days from stent placement

124
Q

What intervention should be done if a patient is found to have severe CAD but needs operation and there is a low risk of bleeding?

A

Do DES and continue anti platelet therapy in perioperative period

125
Q

What intervention should be done if a patient is found to have severe CAD and the case is purely elective?

A

Get a DES + dual anti platelet therapy for one year

Continue ASA in the perioperative period

126
Q

What do you do with therapy if the surgery cannot wait for 30 days after placement of bare metal stent?

A

Continue dual anti platelet therapy in the periop period

127
Q

What do you do with therapy if the surgery cannot wait for 365 days after placement of drug eluting stent?

A

Continue dual anti platelet therapy in periop period

128
Q

What is the cardio toxicity of doxorubicin correlate with?

A

Cumulative dose

Peak plasma concentration

129
Q

What dose of doxorubicin is related to a 10% rise in incidence of cardio toxicity?

A

550 mg/m2

130
Q

What drug increases the toxicity of doxorubicin?

A

Trastuzumab

131
Q

What conditions are associated with a large R wave in V1?

A
Muscular dystrophy
WPw
RVH
Right atrial enlargement 
RV strain 
Posterior wall MI
132
Q

What factors make thermodilution unreliable?

A
Timing of the injectate with the respiratory cycle (inspiration = colder) 
Too-slow injection
Low flow states
Wedged catheter 
Clot
Measurement during electrocautery
133
Q

What will reducing the volume of injectate do to the measured CO?

A

Overestimate it by 5-10% for every 0.5 ml

134
Q

What side effects does inamrinone cause?

A

Hepatic necrosis

TCP

135
Q

What is the treatment for WPW?

A
Procainamide - class 1a sodium channel blocker 
It slows the conduction down so that it increases the refractory period of the myocardium, but preserves the AV node
136
Q

Why is digoxin bad in WPW?

A

Because it increases the atrial conduction causing increased aberrant pathway

137
Q

Why is adenosine bad in WPW?

A

It blocks the AV nose increasing aberrant pathway conduction

138
Q

Where does an IABP sit?

A

In the proximal aorta just distal to the left subclavian artery

139
Q

What are the metabolic changes in aortic cross clamping?

A
Decreased oxygen consumption
Increased SvO2
Decreased CO2 production
Increased catecholamines 
Respiratory alkalosis
Metabolic acidosis
140
Q

What is asynchronous mode in a pacemaker?

A

DOO, VOO, AOO

141
Q

What is DOO?

A

It is asychronous mode meaning the pacemaker will pace at whatever rate it is set on
Dual paced, but not sensing or inhibiting

142
Q

When is asynchronous mode dangerous?

A

When the patient’s rate is higher than the pacemakers because of R on T phenomenon

143
Q

What dose of heparin has been shown to be effective in cases of heparin resistance?

A

75 U/kg

144
Q

What is the action of anti thrombin III?

A

Inhibits thrombin, factor Xa and other clotting factors

145
Q

How does heparin work?

A

It binds heparin which activates it and causes a conformational change that allows for higher affinity for thrombin

146
Q

What are the risk factors for antithrombin III deficiency?

A

Platelets >300 K
Age over 65
Preop heparin

147
Q

What does PCC (prothrombin complex concentrate) contain?

A

Factor II, VII, IX, X

148
Q

When is PCC used?

A

Emergently in intracranial bleed for reversal of warfarin

149
Q

What are the hemodynamic goals for aortic regurgitation?

A

Decreased afterload
High normal heart rate
Maintaining contractility

150
Q

What are the hemodynamic goals for mitral regurgitation?

A

Reduced afterload to improve forward flow

151
Q

What are the risk factors for mitral regurgitation?

A
Advanced age
Posterior or inferior wall MI
Multi vessel disease
Prior MI 
Infarct extension 
Recurrent ischemia
152
Q

What is ACT?

A

It is a functional assessment of the intrinsic and common coagulation pathway

153
Q

What is the Betzold-Jarisch reflex?

A

Paradoxical reflexive bradycardia caused by left ventricular distention mediated by stretch fibers via the vagus nerve in the setting of hypotension in anaphylaxis

154
Q

What is the Bainbridge reflex?

A

Increased heart rate due to atrial stretch receptors

155
Q

What pacemaker setting is appropriate for someone with permanent atrial fibrillation?

A

VVI

156
Q

What pacemaker setting is appropriate for someone with sick sinus syndrome?

A

AAI

157
Q

What should you do if someone is pacemaker dependent going to surgery?

A

Place in asynchronous mode so that electromagnetic interference is not read a intrinsic cardiac activity by pacemaker and it stops pacing

158
Q

Why do we disable the tachyarrythmia mode in an ICD for operation?

A

So that electromagnetic interference isn’t detected as cardiac activity that needs to be shocked and patient gets R on T

159
Q

What mode of pacemaker can cause R on T when only a ventricular lead?

A

DDD due to post-atrial ventricular blanking

160
Q

A high grade stenosis lesion in what vessel would cause AV block?

A

PDA

161
Q

What is the major landmark for a stellate ganglion block?

A

Transverse process of C6

162
Q

What should be used for nausea after a high spinal block?

A

Atropine because it is likely due to more peristalsis after sympathectomy

163
Q

What artery does the middle cardiac vein run with?

A

PDA

164
Q

Where does the great cardiac vein run?

A

Along the AV groove with the LAD

165
Q

Where does the anterior cardiac vein run?

A

With RCA

166
Q

Where does 85% of coronary blood flow to LV empty into?

A

Coronary sinus

167
Q

What vein drains the RV?

A

Anterior cardiac vein

168
Q

Where does 15% of LV blood flow drain into?

A

Thebesian veins

169
Q

What artery does the middle cardiac vein run with?

A

PDA

170
Q

Where does the great cardiac vein run?

A

Along the AV groove with the LAD

171
Q

Where does the anterior cardiac vein run?

A

With RCA

172
Q

Where does 85% of coronary blood flow to LV empty into?

A

Coronary sinus

173
Q

What vein drains the RV?

A

Anterior cardiac vein

174
Q

Where does 15% of LV blood flow drain into?

A

Thebesian veins

175
Q

What patients should be started on a beta blocker perioperatively?

A

Patients with 3 or more risk factors for CAD/MI and having high risk surgery

176
Q

What is the equation for wall tension?

A

Wall tension = LVEDP X radius (of ventricle)/ 2 X wall thickness

177
Q

What are the three main determinants of myocardial oxygen demand?

A

Heart rate
Contractility
Wall tension

178
Q

How does LVH help decrease myocardial oxygen demand?

A

Decreases wall tension by increasing wall thickness

179
Q

What is ST depression a sign of?

A

Acute sub endocardium ischemia

180
Q

What is ST elevation a sign of?

A

Transmitral ischemia or injury

181
Q

What are the characteristics of a pathological Q wave?

A

At least 1 mm or 0.04 ms in width and 1/3 height of the QRS

182
Q

Why is epinephrine the drug of choice in ACLS.

A

The alpha mediated vasoconstriction improved coronary and cerebral perfusion pressure

183
Q

What is a prominent R wave suggestive of?

A
RVH
RV strain (with ST changes)
Posterior wall MI
WPW 
Right atrial enlargement
Muscular dystrophy
184
Q

How much SV does the atrial kick provide in a patient with a normal heart?

A

20%

185
Q

How much SV does the atrial kick provide to a patient with AS?

A

40%

186
Q

What is the ideal heart rate for someone with AS?

A

55-70 bpm

187
Q

How much time should pass before a patient who had a major cardiac event gets noncardiac surgery?

A

Greater than 60 days

188
Q

Which ion are myocytes permeable to?

A

Potassium

189
Q

Which ion are myocytes impermeable to?

A

Na and Ca

190
Q

How does the Na-K ATPase pump work?

A

Moves K in, Na out

191
Q

What is the normal resting potential of a cardiac myocyte?

A

-80-90 mV

192
Q

What maintains the cardiac action potential?

A

Voltage gated calcium channels (L-type)

193
Q

Where is the SA node?

A

At sulcus terminalis, posteriorly at the junction of the right atrium and SVC

194
Q

What causes the SA node to fire?

A

Constant leaking of Na channels, making the membrane potential less negative (toward threshold)

195
Q

Where is the AV node?

A

In the septal wall of the right atrium

Anterior to the opening of the coronary sinus and above the insertion of the septal leaflet of the tricuspid

196
Q

What are the three regions of the AV node?

A

N (middle) - no automaticity
NH (lower junctional)
AN (higher junctional)

197
Q

Why is there a delay in the AV node?

A

It is mediate by L-type calcium channels

198
Q

What ion channel is responsible for the ventricular depol?

A

Sodium channels

199
Q

Which drugs bind L-type calcium channels?

A

Nifedipine
Verapamil
Dilt

200
Q

What is the mechanism of contraction?

A

Intracellular calcium binds troponin C –> conformational change –> exposed sites on actin –> actin/myosin bind

201
Q

When does relaxation occur?

A

When Ca is pumped back into SR by Ca-Mg- ATPase and extracellularly by an ATPase

202
Q

What ion is myosin dependent on?

A

Magnesium

Because the active site on myosin functions as a Mg-dependent ATPase

203
Q

How does sympathetic stimulation affect contractility?

A

B1 mediated increase in camp results in additional calcium channels

204
Q

How do phosphodiesterase inhibitors enhance contractility?

A

By preventing the breakdown do cAMP, thus increasing calcium receptors and thus calcium influx

205
Q

How does digitalis increase contractility?

A

By inhibiting the Na-K ATPase pump, allows Calcium to buildup in cell

206
Q

How does glucagon increase contractility?

A

By increasing cAMP by nonadrenergic pathway

207
Q

How does levosimendan work?

A

Binds to troponin C increasing its sensitivity to Ca

208
Q

How does acidosis affect contractility?

A

Slows calcium channels

209
Q

What is the sympathetic innervation to the heart?

A

T1-4 via the stellate ganglion

210
Q

What is early diastolic compliance?

A

Rate of relaxation

211
Q

What is late diastolic compliance?

A

Passive stiffness of the ventricles

212
Q

What factors influence early diastolic compliance?

A

HTN
Aortic stenosis
A synchrony

213
Q

What factors influence late diastolic compliance?

A
Pericardial disease
Extensive dissension of contralateral ventricle
Increased airway pressure
Pleural pressure
Tumors
Surgical compression
214
Q

What is normal pulmonary vascular resistance?

A

50-150 dyn3/

215
Q

What does the initial rise of the arterial line represent?

A

The change in ventricular pressure over time

216
Q

What are the things that determine diastolic function?

A

Isovolumetric relaxation time
The peak of early diastolic flow (E) to peak atrial systolic flow (A)
Deceleration time of E

217
Q

What e’ wave peak velocity is associated with impaired diastolic filling?

A

Less than 8cm/sec

218
Q

What is a normal E/a ratio?

A

0.8-1.2

219
Q

What is a normal deceleration time of E?

A

150-300 ms

220
Q

What is the E/a ratio of stage II (pseudo normalization)?

A

0.8-1.2

221
Q

What is the E/a ratio of stage I (impaired)?

A

<0.8

222
Q

What is the E/a ratio of stage III

A

> 1.2

223
Q

What is the deceleration time of E in stage I DD?

A

> 250 ms

224
Q

What is the deceleration time of stage III DD?

A

Less than 150 ms

225
Q

What is the sequence of coronary blood flow?

A

Epicardium–>endocardium vessels –> right atrium via coronary sinus and anterior cardiac veins

Some blood goes directly to chambers via thebesian veins

226
Q

How does coronary perfusion pressure work?

A

It is regulated by the myocardium according to deman between perfusion pressures of 50-120mmHg

227
Q

What adrenergic receptors are present in coronary vessels?

A

Beta 2 and alpha

228
Q

What is the most important determinant of myocardial blood flow?

A

Myocardial oxygen demand

229
Q

How much oxygen does the myocardium extract from the blood? What are the implications of this?

A

65%, the myocardium cannot compensate for reductions in blood flow by increasing oxygen extraction. Must increase coronary blood flow instead

230
Q

What is the most taxing thing that require oxygen?

A

Pressure work

231
Q

How are volatile anesthetics helpful in heart failure?

A

Decrease preload and afterload thereby decreasing myocardial oxygen demand.

Protects against reperfusion injury

Enhance recovery of stunned myocardium

232
Q

Why does E/a ratio decrease in stage I?

A

Because early filling is decreased because the pressure gradient is decreased fro, the atrium to ventricle, so the peak velocity of E is reduced, but the atrium contracts normally.

233
Q

Why does the E/a ratio in stage II “normalize”?

A

Because as diastolic dysfunction progresses, the atrial pressure increases restoring the gradient between atrium and ventricle

234
Q

Why does stage III diastolic dysfunction have an increased E/a ratio?

A

The ventricle is so stiff that early filling is quick and the atrium can barely contract against the pressure and thus contributes little to filling

235
Q

What kind of valve disorder does a prominent a wave and a decreased y descent indicate?

A

Mitral stenosis

236
Q

What does a notched P wave on EKG mean?

A

May indicate mitral stenosis

237
Q

What valve area is considered severe mitral stenosis?

A

Less than 1.5 cm

238
Q

What is a normal mitral valve area?

A

4-6 cm

239
Q

In mitral stenosis, what does the PCWP represent?

A

The transvalvular gradient

240
Q

How much regurgitate volume is considered severe?

A

Greater than 60%

RSV Greater than 65 ml

241
Q

What hemodynamics should be avoided in MR?

A

Slow heart rate and acute increases in afterload

Volume overload

242
Q

What valve disorder is associated with a large v wave and a rapid y descent?

A

Mitral regurg

243
Q

What is the v wave proportional to?

A

Pulmonary blood flow and regurgitant volume