Ischemic Heart Disease Flashcards
1
Q
ischemic heart disease is caused by
A
- coronary atherosclerosis
2
Q
myocardial ischemia results from
A
- an imbalance between oxygen supply and oxygen demand
3
Q
how does atherosclerosis disrupt myocardial oxygen supply
A
(1) decreasing coronary artery diameter
(2) disrupting normal endothelial function
4
Q
chief determinants of myocardial oxygen demand
A
- heart rate
- contractility
- wall tension
5
Q
how do we treat chronic stable angina
A
- reduce demand
6
Q
how do we treat coronary syndromes
A
- restore supply
7
Q
most commonly used medications for treatment of chronic stable angina
A
- organic nitrates
- beta blockers
- calcium channel blockers
8
Q
definition of ischemia
A
- interference with blood supply to tissues
9
Q
angina
A
- chest pain due to inadequate supply of oxygen to the heart
10
Q
chief clinical manifestation of myocardial ischemia
A
- angina
11
Q
how does ischemia cause angina
A
- release lactate, serotonin, and adenosine that activates local afferent pain fibers
12
Q
chronic stable angina
A
- predictable transient chest discomfort during exertion or emotional stress
13
Q
chronic stable angina caused by
A
- fixed obstructive plaque in >1 coronary arteries
14
Q
chronic stable angina and myocyte death
A
- not associated with cardiomyocyte death
15
Q
what supplies the oxygen
A
- coronary artery
16
Q
what demands the oxygen
A
- myocardium
17
Q
what is compressed during systole
A
- intramural coronary arteries
18
Q
when is the heart’s oxygen demand the highest
A
- at rest
- due to ATP requirement
19
Q
reserve of oxygen in blood at rest
A
- minimal reserve
20
Q
what is the primary determinant of myocardial oxygen supply
A
- coronary blood flow
21
Q
what is the primary determinant of coronary blood flow
A
- vascular resistance
22
Q
the fate of the myocardium subjected to ischemia depends on
A
- severity and duration of imbalance between oxygen supply and demand
23
Q
phases of myocyte function at low oxygen supply
A
- reversible recovery of myocyte function
- stunned myocardium
- hibernating myocardium
- irreversible myocardial necrosis/infarction
24
Q
regulation of blood flow occurs in which vessels?
A
- smaller resistance vessels
25
we visualize atherosclerosis in which vessels?
- larger epicardial vessels
26
coronary blood flow occurs in which phase?
- diastole
27
relationship of diastolic filling time and heart rate
- increasing heart rate decreases diastolic filling time
28
coronary perfusion pressure formula
aortic diastolic pressure - LVEDP
29
how can coronary perfusion pressure be compromised?
- LVEDP is high
- aortic pressure is low
- as in heart failure
30
what is the major determinant of resistance in blood vessels
- radius
31
coronary arteries are capable of sufficient compensatory dilatation to prevent ischemia until the diameter of the lumen is what
- decreased by > 70%
32
metabolic determinants of vascular tone
results
- acidosis
- hypoxia
- citrate/acetate
- adenosine
all vasodilation
33
endothelial determinant of vascular resistance
results
- nitric oxide
| - vasodilation
34
what is the most known endogenous vasodilator
- nitric oxide
35
how atherosclerosis causes endothelial dysfunction
- impairs endothelial capacity to regulate vascular tone
36
how stress tests work
- provoke and detect a mismatch in supply and demand that causes controlled and transient subendocardial ischemia
37
pharmacologic drugs for stress test
- dobutamine
- adenosine
- dipyridamole
38
when is a stress test considered positive
- typical chest discomfort reproduced
| - > 1 mm ST depression
39
radionucleotide imaging can be added in patients with
- abnormal baseline ECG
| - high clinical suspicion of ischemic heart disease
40
cause of a reversible defect: perfused at rest, but not after stress
- inducible ischemia
41
cause of fixed defect: no perfusion at rest or after stress
- prior MI and fibrosis
42
coronary angiography reserved for which patients:
- anginal symptoms not respond to drug therapy
- unstable presentation
- noninvasive test is abnormal
43
what is the gold standard for CAD
- coronary angiography
44
what do endothelial cells release
- paracrine vasodilatory signals
45
non-selective beta blockers
- propranolol
| - nadolol
46
cardioselective beta blockers
- atenolol
- metoprolol
- esmolol
47
mixed selective beta blockers
- carvedilol
| - labetalol
48
contraindications of beta blockers
- severe bronchospastic disease
- severe decompensated heart failure
- severe bradycardia
- AV block
49
calcium channel blockers MOA
- block L type calcium channel
50
dihydropyridines
- all the -dipines
51
non-dihydropyridines
- verapamil
| - diltiazem
52
what do dihydropyridine calcium channel blockers act on
- vascular smooth muscle
53
physiological effects of both classes of calcium channel blockers
- arterial vasodilation
54
result of arterial vasodilation
- increased coronary blood flow
| - decreased blood pressure
55
physiologic effects of non-DHP calcium channel blockers
- prolonged AV conduction
| - negative inotropy
56
result of prolonged AV conduction
- decreased heart rate
| - increased diastolic time
57
result of negative inotropy
- decreased oxygen demand
58
what line of therapy are calcium channel blockers?
- second line therapy
59
contraindications for calcium channel blockers
- systolic heart failure
- bradycardia
- sinus node dysfunction
- AV nodal block
60
organic nitrates serve as
- nitric oxide donors
61
MOA of organic nitrates
- venodilation
| - arteriodilation
62
result of venodilation
- decreased venous return
- decreased wall tension
- decreased oxygen demand
63
result of arteriodilation
- increased coronary blood flow
| - increased oxygen demand
64
what is sublingual nitroglycerin used to treat
- acute episodes of angina
65
what do we use for prevention of chronic stable angina
- isosorbide mononitrate
| - denigrate
66
contraindication for organic nitrates
- PDE-5 inhibitors like viagra
67
what do we use for secondary prevention
- aspirin
| - statins
68
first line treatment of stable angina
- beta blockers and nitrates to reduce demand
| - aspirin and statins to prevent worsening atherosclerosis and ACS
69
what if angina persists despite medical therapy
- use PCI
70
does PCI change mortality
- no
71
how does a CABG work?
- 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
when is CAB preferred over PCI
- 50% of left main coronary artery
- 3 vessel disease - LAD, Lcx, RCA
- 2 vessel disease - LAD with low ejection fraction or diabetes
