Ischemic Heart Disease Flashcards

1
Q

ischemic heart disease is caused by

A
  • coronary atherosclerosis
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2
Q

myocardial ischemia results from

A
  • an imbalance between oxygen supply and oxygen demand
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3
Q

how does atherosclerosis disrupt myocardial oxygen supply

A

(1) decreasing coronary artery diameter

(2) disrupting normal endothelial function

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4
Q

chief determinants of myocardial oxygen demand

A
  • heart rate
  • contractility
  • wall tension
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5
Q

how do we treat chronic stable angina

A
  • reduce demand
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6
Q

how do we treat coronary syndromes

A
  • restore supply
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7
Q

most commonly used medications for treatment of chronic stable angina

A
  • organic nitrates
  • beta blockers
  • calcium channel blockers
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8
Q

definition of ischemia

A
  • interference with blood supply to tissues
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9
Q

angina

A
  • chest pain due to inadequate supply of oxygen to the heart
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10
Q

chief clinical manifestation of myocardial ischemia

A
  • angina
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11
Q

how does ischemia cause angina

A
  • release lactate, serotonin, and adenosine that activates local afferent pain fibers
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12
Q

chronic stable angina

A
  • predictable transient chest discomfort during exertion or emotional stress
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13
Q

chronic stable angina caused by

A
  • fixed obstructive plaque in >1 coronary arteries
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14
Q

chronic stable angina and myocyte death

A
  • not associated with cardiomyocyte death
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15
Q

what supplies the oxygen

A
  • coronary artery
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16
Q

what demands the oxygen

A
  • myocardium
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17
Q

what is compressed during systole

A
  • intramural coronary arteries
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18
Q

when is the heart’s oxygen demand the highest

A
  • at rest

- due to ATP requirement

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19
Q

reserve of oxygen in blood at rest

A
  • minimal reserve
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20
Q

what is the primary determinant of myocardial oxygen supply

A
  • coronary blood flow
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21
Q

what is the primary determinant of coronary blood flow

A
  • vascular resistance
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22
Q

the fate of the myocardium subjected to ischemia depends on

A
  • severity and duration of imbalance between oxygen supply and demand
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23
Q

phases of myocyte function at low oxygen supply

A
  • reversible recovery of myocyte function
  • stunned myocardium
  • hibernating myocardium
  • irreversible myocardial necrosis/infarction
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24
Q

regulation of blood flow occurs in which vessels?

A
  • smaller resistance vessels
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25
Q

we visualize atherosclerosis in which vessels?

A
  • larger epicardial vessels
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26
Q

coronary blood flow occurs in which phase?

A
  • diastole
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27
Q

relationship of diastolic filling time and heart rate

A
  • increasing heart rate decreases diastolic filling time
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28
Q

coronary perfusion pressure formula

A

aortic diastolic pressure - LVEDP

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29
Q

how can coronary perfusion pressure be compromised?

A
  • LVEDP is high
  • aortic pressure is low
  • as in heart failure
30
Q

what is the major determinant of resistance in blood vessels

A
  • radius
31
Q

coronary arteries are capable of sufficient compensatory dilatation to prevent ischemia until the diameter of the lumen is what

A
  • decreased by > 70%
32
Q

metabolic determinants of vascular tone

results

A
  • acidosis
  • hypoxia
  • citrate/acetate
  • adenosine

all vasodilation

33
Q

endothelial determinant of vascular resistance

results

A
  • nitric oxide

- vasodilation

34
Q

what is the most known endogenous vasodilator

A
  • nitric oxide
35
Q

how atherosclerosis causes endothelial dysfunction

A
  • impairs endothelial capacity to regulate vascular tone
36
Q

how stress tests work

A
  • provoke and detect a mismatch in supply and demand that causes controlled and transient subendocardial ischemia
37
Q

pharmacologic drugs for stress test

A
  • dobutamine
  • adenosine
  • dipyridamole
38
Q

when is a stress test considered positive

A
  • typical chest discomfort reproduced

- > 1 mm ST depression

39
Q

radionucleotide imaging can be added in patients with

A
  • abnormal baseline ECG

- high clinical suspicion of ischemic heart disease

40
Q

cause of a reversible defect: perfused at rest, but not after stress

A
  • inducible ischemia
41
Q

cause of fixed defect: no perfusion at rest or after stress

A
  • prior MI and fibrosis
42
Q

coronary angiography reserved for which patients:

A
  • anginal symptoms not respond to drug therapy
  • unstable presentation
  • noninvasive test is abnormal
43
Q

what is the gold standard for CAD

A
  • coronary angiography
44
Q

what do endothelial cells release

A
  • paracrine vasodilatory signals
45
Q

non-selective beta blockers

A
  • propranolol

- nadolol

46
Q

cardioselective beta blockers

A
  • atenolol
  • metoprolol
  • esmolol
47
Q

mixed selective beta blockers

A
  • carvedilol

- labetalol

48
Q

contraindications of beta blockers

A
  • severe bronchospastic disease
  • severe decompensated heart failure
  • severe bradycardia
  • AV block
49
Q

calcium channel blockers MOA

A
  • block L type calcium channel
50
Q

dihydropyridines

A
  • all the -dipines
51
Q

non-dihydropyridines

A
  • verapamil

- diltiazem

52
Q

what do dihydropyridine calcium channel blockers act on

A
  • vascular smooth muscle
53
Q

physiological effects of both classes of calcium channel blockers

A
  • arterial vasodilation
54
Q

result of arterial vasodilation

A
  • increased coronary blood flow

- decreased blood pressure

55
Q

physiologic effects of non-DHP calcium channel blockers

A
  • prolonged AV conduction

- negative inotropy

56
Q

result of prolonged AV conduction

A
  • decreased heart rate

- increased diastolic time

57
Q

result of negative inotropy

A
  • decreased oxygen demand
58
Q

what line of therapy are calcium channel blockers?

A
  • second line therapy
59
Q

contraindications for calcium channel blockers

A
  • systolic heart failure
  • bradycardia
  • sinus node dysfunction
  • AV nodal block
60
Q

organic nitrates serve as

A
  • nitric oxide donors
61
Q

MOA of organic nitrates

A
  • venodilation

- arteriodilation

62
Q

result of venodilation

A
  • decreased venous return
  • decreased wall tension
  • decreased oxygen demand
63
Q

result of arteriodilation

A
  • increased coronary blood flow

- increased oxygen demand

64
Q

what is sublingual nitroglycerin used to treat

A
  • acute episodes of angina
65
Q

what do we use for prevention of chronic stable angina

A
  • isosorbide mononitrate

- denigrate

66
Q

contraindication for organic nitrates

A
  • PDE-5 inhibitors like viagra
67
Q

what do we use for secondary prevention

A
  • aspirin

- statins

68
Q

first line treatment of stable angina

A
  • beta blockers and nitrates to reduce demand

- aspirin and statins to prevent worsening atherosclerosis and ACS

69
Q

what if angina persists despite medical therapy

A
  • use PCI
70
Q

does PCI change mortality

A
  • no
71
Q

how does a CABG work?

A
  • left internal mammary artery freed from chest wall and attached to LAD
  • saphenous veins removed from legs and grafted from ascending aorta to coronary arteries
72
Q

when is CAB preferred over PCI

A
  • 50% of left main coronary artery
  • 3 vessel disease - LAD, Lcx, RCA
  • 2 vessel disease - LAD with low ejection fraction or diabetes