293 Ischemic Heart Disease Flashcards

1
Q

Condition in which there is an inadequate supply of blood and oxygen to a portion of the myocardium

A

Ischemic Heart Disease (IHD)

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2
Q

Occurs due to imbalance between myocardial oxygen supply and demand

A

IHD

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3
Q

Most common cause of myocardial ischemia

A

Atherosclerotic disease of epicardial coronary artery/-ies

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4
Q

Most common, serious, chronic, life-threathening illness in US

A

IHD

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5
Q

Factors associated with emergence of IHD

A
  1. Genetic
  2. High fat and energy rich diet
  3. Smoking
    4 Sedentary lifestyle
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6
Q

Powerful risk factors for IHD

A
  1. Obesity
  2. Insulin resistance
  3. Type 2 Diabetes mellitus
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7
Q

Major determinants of myocardial oxygen demand (MVO2)

A
  1. Heart rate
  2. Myocardial contractility
  3. Myocardial wall tension (stress)
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8
Q

Determines the oxygen-carrying capacity of the blood

A
  1. Inspired level of oxygen
  2. Pulmonary function
  3. Hemoglobin concentration and function
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9
Q

Requirement to have adequate supply of oxygen to myocardium

A
  1. Satisfactory level of oxygen-carrying capacity of the blood
  2. Adequate level of coronary blood flow
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10
Q

Blood flow through the coronary arteries in what phase of cardiac cycle

A

Diastole

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11
Q

Arteries responsible for the total coronary resistance to flow

A
  1. large epicardial arteries (Resistance 1 = R1)
  2. prearteriolar vessels R2
  3. arteriolar and intramyocardial capillary vessels R3
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12
Q

Major determinant of coronary resistance

A

R2 and R3

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13
Q

What dominates and controls the normal coronary circulation?

A

OXYGEN requirement of the heart

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14
Q

Mechanism of myocardial ischemia in severe left ventricular hypertrophy (due to aortic stenosis)

A
  1. Myocardial oxygen demands markedly increased

2. Coronary blood flow may be limited

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15
Q

T or F: Extremely severe anemia can cause myocardial ischemia.

A

False.

Rarely cause myocardial ischemia BY ITSELF but may lower threshold for ischemia in patients with moderate coronary obstruction

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16
Q

Abnormal constriction or failure of normal dilation of the coronary resistance vessels can cause ischemia, producing angina. What condition is this?

A

Microvascular angina

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17
Q

Major site of atherosclerotic disease

A

Epicardial coronary arteries

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18
Q

Major risk factors for ATHEROSCLEROSIS

A
  1. High LDL
  2. Low HDL
  3. Cigarette smoking
  4. Hypertension
  5. Diabetes mellitus
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19
Q

Normal function of vascular endothelium

A
  1. Local control of vascular tone
  2. Maintenance of antithrombotic surface
  3. Control of inflammatory cell adhesion and diapedesis
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20
Q

Effects of dysfunctional vascular endothelium

A
  1. Inappropriate constriction
  2. Luminal thrombus formation
  3. Abnormal interactions between blood cells (monocytes, platelets)
  4. Activated vascular endothelium (proinflammatory and prothrombotic)
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21
Q

Collection of fat, smooth muscle cells, fibroblasts and intercellular matrix

A

Atherosclerotic plaque

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22
Q

State of diabetics which make them vulnerable to atherosclerosis

A

HYPERcoagulability and

HYPOfibrinolysis

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23
Q

Site of predilection for atherosclerotic plaques to develop

A

Sites of increased turbulence in coronary flow (e.g. branch points)

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24
Q

Reduction in diameter of epicardial artery by what percentage causes limitation of ability to increase flow to meet increased myocardial demand

A

50%

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25
Q

Reduction in diameter of epicardial artery by what percentage causes reduced blood flow at rest and cause myocardial ischemia at rest or with minimal stress

A

80%

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26
Q

2 processes that occur when a plaque is exposed in the blood after rupture or erosion

A
  1. Platelets are activated and aggregate
  2. Coagulation cascade is activated = deposition of fibrin strands

Product: Thrombus

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27
Q

Mechanism of myocardial ischemia

A

Thrombus (platelet aggregates + fibrin strands) traps RBC and reduce coronary blood flow = clinical manifestations of ischemia

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28
Q

T or F: Collateral vessels when formed can provide sufficient blood flow to sustain the myocardium at rest and during conditions of increased demand

A

False

Can sustain myocardium at rest BUT NOT during conditions of increased demand

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29
Q

Duration of time that the damages of total occlusion are reversible

A

Less than or equal to 20 minutes

More than that, it is permanent with subsequent myocardial necrosis

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30
Q

A common presenting manifestation of IHD

A

Sudden death

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31
Q

Patients with IHD presenting with cardiomegaly and heart failure

A

Ischemic cardiomyopathy

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32
Q

T or F: In ischemic cardiomyopathy, patients can have no symptoms before the development of heart failure

A

True

This is the asymptomatic phase of IHD

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33
Q

T or F: In IHD, once you have entered the symptomatic phase, reverting back to asymptomatic stage will be impossible.

A

False

Patient may revert from symptomatic to asymptomatic or even die suddenly

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34
Q

The sign describing angina as squeezing, central, substernal discomfort and placing a clenched fist over the sternum

A

Levine’s sign

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35
Q

T or F: Chest discomfort in angina can also radiate to the trapezius muscles

A

False

Myocardial ischemic discomfort DOES NOT radiate to trapezium muscles; pattern is more typical of PERICARDITIS

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36
Q

Radiations of angina

A
  1. Either shoulder
  2. Both arms (ulnar surfaces of forearm and hand)
  3. Back
  4. Interscapular region
  5. Root of neck
  6. Jaw
  7. Teeth
  8. Epigastrium

Rarely below umbilicus or above mandible

37
Q

Difference of the Canadian Cardiac Society functional classification and New York Heart Association functional classification

A

CCS FC : Severity of angina
NYHA FC: Impact on patient’s functional capacity

See Table 293-1, p. 1581

38
Q

Anginal “equivalents”

A
  1. Dyspnea
  2. Nausea
  3. Fatigue
  4. Faintness
39
Q

Special population where anginal equivalents are more common

A
  1. Elderly

2. Diabetic patients

40
Q

Cut-off age for premature IHD

A

<55 years in first-degree male relatives

<65 years in female relatives

41
Q

Establishes the diagnosis of IHD

A

History of typical angina pectoris

42
Q

Increases likelihood of coronary disease in patients

A
  1. advance age
  2. male sex
  3. postmenopausal state
  4. risk factors for atherosclerosis
43
Q

Independent risk factor for IHD

A

high-sensitivity C-reactive protein (CRP)

between 0 and 3mg/dl

44
Q

Laboratories for IHD patients

A
  1. Urinalysis
  2. Lipid profile
  3. Glucose (HBA1C)
  4. Creatinine
  5. Hematocrit
  6. Thyroid function test (IF INDICATED)
  7. Chest x-ray
45
Q

Most widely used test for both diagnosis of IHD and estimation of risk and prognosis

A

Stress testing

46
Q

When is stress test discontinued?

A
  1. Evidence of chest discomfort
  2. Severe shortness of breath
  3. Dizziness
  4. Severe fatigue
  5. ST segment depression >0.2mV (2mm)
  6. Fall in systolic BP >10mmHg
  7. Development of ventricular tachyarrhythmia
47
Q

Definition of ischemic ST-segment response (positive test)

A

Flat or downsloping depression of the ST segment >0.1 mV below baseline (i.e. PR segment) and lasting longer than 0.08s

48
Q

Negative for stress test

A
  1. Upsloping or junctional ST segment changes
  2. T-wave abnormalities
  3. Conduction disturbances
  4. Ventricular arrhythmias
  5. Target heart rate (85% of maximal predicted heart rate for age and sex) not achieved
49
Q

Conditions that increases incidence of false positive result in stress test

A
  1. Asymptomatic men age <40
  2. Premenopausal women with no risk factors for premature atherosclerosis
  3. Patients taking cardioactive drugs (digitalis, anti arrhythmic agents)
  4. Intraventricular conduction disturbances
  5. Resting ST segment and T wave abnormalities
  6. Ventricular hypertrophy
  7. Abnormal serum potassium levels
50
Q

Contraindications to stress test

A
  1. Rest angina within 48h
  2. Unstable rhythm
  3. Severe aortic stenosis
  4. Acute myocarditis
  5. Uncontrolled heart failure
  6. Severe pulmonary hypertension
  7. Active infective endocarditis
51
Q

Interpret result: Patient who underwent stress test developed angina and severe ST-segment depression (>0.2mV) at low workload that persisted for more than 5 mins after the termination of exercise

A

Suggests severe IHD and high risk of future adverse events

52
Q

What radioactive isotope is injected in performing stress myocardial radionuclide perfusion imaging?

A

Thallium-201 or 99m-technetium sestamibi

53
Q

Alternative for patients who cannot tolerate exercise, who need stress testing

A

Use intravenous pharmacologic challenge

  1. Dipyridamole or Adenosine
  2. Dobutamine
54
Q

Used to assess left ventricular function in patients with chornic stable angina and patients with history of prior MI, pathologic Q waves, or clinical evidence of heart failure

A

Echocardiography

55
Q

More sensitive than exercise ECG in diagnosis of IHD

A

Stress echocardiography

56
Q

Diagnostic method that outline the lumina of the coronary arteries and can be used to detect or exclude serious coronary obstruction

A

Coronary arteriography

57
Q

Indications for coronary arteriography

A
  1. Patients with chronic stable angina pectoris who are severely symptomatic despite medical therapy and are bring considered for revascularization (PCI or CABG)
  2. Patients with troublesome symptoms that present diagnostic difficulties in whom there is a need to confirm or rule out the diagnosis of IHD
  3. Patient with known or possible angina pectoris who have survived cardiac arrest
  4. Patients with angina or evidence of ischemia on noninvasive testing with clinical or lab evidence of ventricular dysfunction
  5. Patients judged to be at high risk of sustaining coronary events based on signs of severe ischemia on noninvasive testing, regardless of presence or severity of symptoms

Read other examples of other indications on pp. 1585-1586

58
Q

Alternatives to diagnostic coronary arteriography

A

CT angiography

Cardiac magnetic resonance (CMR) angiography

59
Q

Principal prognostic indicators in patients with IHD

A
  1. Age
  2. Functional state of left ventricle
  3. Location(s) and severity of coronary artery narrowing
  4. Severity or activity of myocardial ischemia
60
Q

Signs indicating high risk for coronary events during noninvasive testing

A
  1. Inability to exercise for 6 min (Stage II [Bruce protocol] of exercise test)
  2. Strongly positive exercise test showing onset of myocardial ischemia at low workloads
  3. development of large or multiple perfusion defects or increased lung uptake during stress radioisotope perfusion imaging
  4. Decrease in LV ejection fraction during exercise on radionuclide ventriculography or during stress echocardiography
61
Q

Strongly positive exercise test

A
  1. > /=0.1 mV ST-segment depression before completion of stage II
  2. > /=0.2mV ST-segment depression at ANY stage
  3. ST segment depression for >5 min after cessation of exercise
  4. Decline in systolic pressure >10mmHg during exercise
62
Q

Most important signs of left ventricular dysfunction associated with poor prognosis on cardiac catheterization

A
  1. Elevated left ventricular end diastolic pressure and ventricular volume
  2. Reduced ejection fraction
63
Q

Management plan for stable angina pectoris

A
  1. Explanation of problem and reassurance
  2. Identify and treat aggravating conditions
  3. Recommendations for adaptation of activity as needed
  4. treatment of risk factors that will decrease occurrence of adverse coronary outcomes
  5. Drug therapy
  6. Consideration of revascularization
64
Q

Major mechanism of this drug is systemic venodilation with concomitant reduction in LV end-diastolic volume and pressure, thereby reducing myocardial wall tension and oxygen requirements

A

Nitrates

65
Q

Reason why nitroglycerin is administered sublingually

A

Absorption is most rapid and complete through the mucus membranes

66
Q

Reason why nitrates should have minimum of 8h each day kept free from the drug

A

Tolerance

67
Q

Reduce myocardial oxygen demand by inhibiting the increase in heart rate, arterial pressure, and myocardial contractility

A

Beta adrenergic blockers

68
Q

Beta 1 selective drugs

A
  1. Acetabulol
  2. Atenolol
  3. Betaxolol
  4. Bisoprolol
  5. Esmolol (IV)
  6. Metoprolol
  7. Nebivolol (at low doses)
69
Q

Coronary vasodilators that produce variable and dose-dependent reduction in myocardial oxygen demand, contractility, and arterial pressure

A

Calcium channel blockers

70
Q

Drugs indicated when beta blockers are contraindicated, poorly tolerated or ineffective

A

Calcium channel blockers

71
Q

Drugs that are avoided for IHD patients since they exert negative inotropic actions and likely to aggravate LV failure

A

Nondihydropyridine calcium channel blockers (verapamil, diltiazem)

72
Q

Indications for calcium channel blockers

A
  1. Inadequate responsiveness to combination of beta blockrs and nitrates
  2. adverse reaction to beta blockers (depression, sexual disturbance, fatigue)
  3. angina and history of asthma or COPD
  4. Sick-sinus syndrome or significant atrioventricular conduction disturbances
  5. Prinzmetal’s angina
  6. Symptomatic peripheral arterial disease
73
Q

Irreversible inhibitor of platelet cyclooxygenase and thereby interferes with platelet activation

A

Aspirin

75-325mg orally per day

74
Q

Oral agent that blocks P2Y12 ADP receptor-mediated platelet aggregation

A

Clopidogrel

300-600mg loading and 75mg/d
Use if intolerant to Aspirin

75
Q

How long should dual antiplatelet therapy be given in patient with acute coronary syndrome?

A

At least a year

76
Q

A piperazine derivative useful in patients with chronic angina despite standard medical therapy; inhibits late inward sodium current thereby limiting Na and Ca overload

A

Ranolazine

77
Q

Contraindications for Ranolazine

A
  1. Patient with hepatic impairment
  2. Conditions or drugs associated with QTc prolongation
  3. Drugs that inhibit CYP3A metabolic system (ketoconazole, diltiazem, verapamil, macrolides, HIV protease inhibitors, large quantities of grapefruit juice)
78
Q

Opens ATP-sensitive potassium channels in myocytes leading to a reduction of free intracellular calcium ions

A

Nicorandil

79
Q

Involves balloon dilation usually accompanied by coronary stenting to achieve revascularization of myocardium in symptomatic IHD

A

Percutaneous coronary intervention (PCI)

80
Q

Most common clinical indication for PCI

A

symptom-limiting angina pectoris despite medical therapy accompanied by evidence of ischemia during stress test

81
Q

T or F: PCI is more effective than medical therapy for the relief of angina.

A

True

82
Q

T or F: Left main coronary artery stenosis generally is regarded as indication to PCI

A

False.

Regarded as contraindication to PCI

83
Q

Anastomosis of one or both of internal mammary arteries or a radial artery to the coronary artery distal to the obstructive lesion

A

Coronary Artery Bypass Grafting

84
Q

Effects of CABG

A

See pp.1591-1592

85
Q

Stroke rates are lower with PCI? or CABG?

A

PCI

86
Q

PCI or CABG: Patient with single or two vessel disease and normal LV function

A

PCI

87
Q

Patients with three-vessel disease and impaired global LV function (EF <50%) or DM and those with left main CAD

A

CABG should be considered

88
Q

Utilizes pneumatic cuffs on the lower extremities to provide diastolic augmentation and systolic unloading of BP to decrease cardiac work and oxygen consumption while enhancing coronary blood flow

A

Enhanced external couterpulsation

89
Q

T or F: Patients with asymptomatic ischemia after MI are at greater risk for a second coronary event

A

True