295 ST Segment Elevation Myocardial Infarction

Question 1

It occurs when coronary blood flow decreases abruptly after a thrombotic occlusion of a coronary artery previously affected by atherosclerosis.

Answer 1

STEMI

Question 2

It is the most common presenting complaint in patients with STEMI.

Answer 2

Pain

Question 3

Less common sites of radia- tion of chest pain include _________

Answer 3

abdomen, back, lower jaw, and neck

Question 4

True or False

The pain of STEMI may radiate as high as the occipital area but not below the umbilicus.

Answer 4

True

Question 5

True or False

Pain is not uniformly present in patients with STEMI.

Answer 5

True

Question 6

True or False

One-half with anterior infarction show evidence of parasympathetic hyperactiv- ity (bradycardia and/or hypotension).

Answer 6

False

Question 7

True or False

One-half with inferior infarction show evidence of parasympathetic hyperactiv- ity (bradycardia and/or hypotension).

Answer 7

True

Question 8

True or False

One-fourth of patients with anterior infarction have manifestations of sympathetic nervous system hyperactivity (tachycardia and/or hypertension)

Answer 8

True

Question 9

It rises within 4–8 h and generally returns to normal by 48–72 h

Answer 9

CK

Question 10

True or False

The nonspecific reaction to myocardial injury is associated with polymorphonuclear leukocytosis, the white blood cell count often reaches levels of 12,000–15,000/μL.

Answer 10

True

Question 11

Classification of MI

Spontaneous myocardial infarction related to atherosclerotic plaque rupture, ulceration, fissuring, erosion, or dissection with resulting intraluminal throm- bus in one or more of the coronary arteries leading to decreased myocardial blood flow or distal platelet emboli with ensuing myocyte necrosis. The patient may have underlying severe coronary artery disease (CAD) but on occasion nonobstructive or no CAD.

Answer 11

Type 1: Spontaneous MI

Question 12

Classification of MI

Cardiac death with symptoms suggestive of myocardial ischemia and pre- sumed new ischemic electrocardiogram (ECG) changes or new left bundle branch block (LBBB), but death occurring before blood samples could be obtained or before cardiac biomarker could rise, or in rare cases, cardiac bio- markers were not collected.

Answer 12

Type 3: Myocardial Infarction Resulting in Death When Biomarker Values Are Unavailable

Question 13

Classification of MI

In instances of myocardial injury with necrosis where a condition other than CAD contributes to an imbalance between myocardial oxygen supply and/ or demand, e.g., coronary endothelial dysfunction, coronary artery spasm, coronary embolism, tachy-brady-arrhythmias, anemia, respiratory failure, hypotension, and hypertension with or without left ventricular hypertrophy.

Answer 13

Type 2: Myocardial Infarction Secondary to an Ischemic Imbalance

Question 14

Classification of MI

It is detected by coronary angiography or autopsy in the setting of myocardial ischemia and with a rise and/or fall of cardiac biomarker values with at least one value above the 99th percentile URL.

Answer 14

Type 4b: Myocardial Infarction Related to Stent Thrombosis

Question 15

Classification of MI

It is arbitrarily defined by elevation
of cardiac troponin (cTn) values >5 × 99th percentile upper reference limit (URL) in patients with normal baseline values (≤99th percentile URL) or a rise of cTn values >20% if the baseline values are elevated and are stable or falling.

Answer 15

Type 4a: Myocardial Infarction Related to Percutaneous Coronary Intervention (PCI)

Question 16

Classification of MI

It is arbitrarily defined by eleva- tion of cardiac biomarker values >10 × 99th percentile URL in patients with normal baseline cTn values (≤99th percentile URL). In addition, either (i) new pathologic Q waves or new LBBB, or (ii) angiographic documented new graft or new native coronary artery occlusion, or (iii) imaging evidence of new loss of viable myocardium or new regional wall motion abnormality.

Answer 16

Type 5: Myocardial Infarction Related to Coronary Artery Bypass Grafting (CABG)

Question 17

Most out- of-hospital deaths from STEMI are due to the sudden development of ______

Answer 17

Ventricular fibrillation

Question 18

Rapid inhibition of cyclooxygenase-1 in plate- lets followed by a reduction of thromboxane A levels is achieved by buccal absorption of a chewed 160–325-mg tablet in the Emergency Department

Answer 18

Aspirin

Question 19

True or False

In patients whose arterial O2 saturation is normal, supplemental O2 is of limited if any clinical benefit and therefore is not cost-effective.

Answer 19

True

Question 20

It can be given safely to most patients with STEMI. Up to three doses of 0.4 mg should be administered at about 5-min intervals.

Answer 20

Sublingual nitroglycerin

Question 21

It is a very effective analgesic for the pain associated with STEMI. It is routinely administered by repetitive (every 5 min) intravenous injection of small doses (2–4 mg), rather than by the subcutaneous administration of a larger quantity, because absorp- tion may be unpredictable by the latter route.

Answer 21

Morphine

Question 22

They are also useful in the control of the pain of STEMI. These drugs control pain effectively in some patients, pre- sumably by diminishing myocardial O2 demand and hence ischemia. They also reduce the risks of reinfarction and ventricular fibrillation

Answer 22

Intravenous beta blockers

Question 23

True or False

Fifteen minutes after the last intravenous dose of beta blocker, an oral regimen is initiated of 50 mg every 6 h for 48 h, followed by 100 mg every 12 h.

Answer 23

True

Question 24

They can impair infarct healing and increase the risk of myocardial rupture, and their use may result in a larger infarct scar. In addition, they can increase coronary vascular resistance, thereby potentially reducing flow to ischemic myocardium.

Answer 24

Glucocorticoids and nonsteroidal anti-inflammatory agents

Question 25

It is generally preferred when the diagnosis is in doubt, cardiogenic shock is present, bleeding risk is increased, or symptoms have been present for at least 2–3 h when the clot is more mature and less easily lysed by fibrinolytic drugs.

Answer 25

Primary PCI

Question 26

TIMI Grading System

It indicates some penetration of the contrast material beyond the point of obstruction but without perfusion of the distal coronary bed

Answer 26

Grade 1

Question 27

TIMI Grading System

It indicates perfusion of the entire infarct vessel into the distal bed, but with flow that is delayed compared with that of a normal artery

Answer 27

Grade 2

Question 28

TIMI Grading System

It indicates com- plete occlusion of the infarct-related artery

Answer 28

Grade 0

Question 29

TIMI Grading System

It indicates full perfusion of the infarct vessel with normal flow

Answer 29

Grade 3

Question 30

current recommended regimen of tPA

Answer 30

15-mg bolus followed by 50 mg intravenously over the first 30 min, followed by 35 mg over the next 60 min

Question 31

current recommended regimen of Streptokinase

Answer 31

1.5 million units (MU) intravenously over 1 h

Question 32

current recommended regimen of rPA

Answer 32

double-bolus regimen consisting of a 10-MU bolus given over 2–3 min, followed by a second 10-MU bolus 30 min later

Question 33

current recommended regimen of TNK

Answer 33

single weight-based intravenous bolus of 0.53 mg/ kg over 10 s

Question 34

Clear contraindications to the use of fibrinolytic agents

Answer 34

history of cerebrovascular hemorrhage at any time

a nonhemorrhagic stroke or other cerebrovascular event within the past year

marked hypertension (a reliably determined systolic arterial pressure >180 mmHg and/or a diastolic pressure >110 mmHg) at any time during the acute presentation

suspicion of aortic dissection

active internal bleeding (excluding menses)

Question 35

Relative contraindications to fibrinolytic therapy

Answer 35

current use of anti- coagulants (international normalized ratio ≥2)

a recent (<2 weeks) invasive or surgical procedure or prolonged (>10 min) cardiopulmonary resuscitation

known bleeding diathesis

pregnancy

a hemorrhagic ophthalmic condition (e.g., hemorrhagic diabetic retinopathy)

active peptic ulcer disease

history of severe hypertension that is currently adequately controlled

Question 36

True or False

It is safe to perform a gentle rectal examination on patients with STEMI.

Answer 36

True

Question 37

Inhibitors of the P2Y12 ADP receptor

Answer 37

Clopidogrel, Prasugrel, Ticagrelor

Question 38

recommended dose of UFH

Answer 38

initial bolus of 60 U/kg (maximum 4000 U) followed by an initial infusion of 12 U/kg per hour (maximum 1000 U/h)

Question 39

True or False

Serum magnesium should be measured in all patients on admission, and any demonstrated deficits should be corrected to minimize the risk of arrhythmias.

Answer 39

True

Question 40

It is now the primary cause of in-hospital death from STEMI.

Answer 40

Pump failure

Question 41

Killip Classification

severe heart failure, pulmonary edema

Answer 41

Class III

Question 42

Killip Classification

no signs of pulmonary or venous conges- tion

Answer 42

Class I

Question 43

Killip Classification

moderate heart failure as evidenced by rales at the lung bases, S3 gallop, tachypnea, or signs of failure of the right side of the heart, including venous and hepatic congestion

Answer 43

Class II

Question 44

Killip Classification

shock with systolic pressure <90 mmHg and evidence of peripheral vasoconstriction, peripheral cyanosis, mental confusion, and oliguria

Answer 44

Class IV

Question 45

To reduce the risk of arrhythmia, the serum K concentration should be adjusted to approximately ________ and magnesium to about ________

Answer 45

K- 4.5 mmol/L

Mg- 2.0 mmol/L

Question 46

True or False

To prevent ventricular tachycardia and fibrillation, routine prophylactic antiarrhythmic drug therapy is
recommended

Answer 46

False

Question 47

Treatment for ventricular tachycardia in STEMI

Answer 47

intravenous regimen of amio- darone (bolus of 150 mg over 10 min, followed by infusion of 1.0 mg/min for 6 h and then 0.5 mg/min) or procainamide (bolus of 15 mg/kg over 20–30 min; infusion of 1–4 mg/min)

Electroversion: unsynchro- nized discharge of 200–300 J (monophasic waveform; approximately 50% of these energies with biphasic waveforms)

Question 48

It is usually the treatment of choice for supraventricular arrhythmias if heart failure is present.

Answer 48

Digoxin

Question 49

Treatment of supra ventricular arrhythmias without heart failure

Answer 49

beta blockers, verapamil, or diltiazem

Question 50

It is the most common supraventricular arrhythmia.

Answer 50

Sinus tachycardia

Question 51

It is the most useful drug for increasing heart rate and should be given intravenously in doses of 0.5 mg initially

Answer 51

Atropine

Question 52

The usual duration of hospitalization for an uncomplicated STEMI

Answer 52

5 days

Question 53

During this period, the patient should be encouraged to increase activity by walking about the house and out- doors in good weather. Normal sexual activity may be resumed during this period.

Answer 53

First 1-2 weeks of convalescent phase

Question 54

Most patients will be able to return to work within _____

Answer 54

2-4 weeks