The AHA Guidelines and Scientific Statements Handbook

Chapter 3 ST-Elevation Myocardial Infarction

initial dose should be 162 mg (Level of Evidence: A)
to 325 mg (Level of Evidence: C). Although some
trials have used enteric-coated aspirin for initial
dosing, more rapid buccal absorption occurs with
non-enteric-coated aspirin formulations.

e. Beta-blockers [2]
Class I
1 Oral beta-blocker therapy should be initiated in
the fi rst 24 hours for patients who do not have any
of the following: (1) signs of heart failure; (2) evi-
dence of a low output state; (3) increased risk* for
cardiogenic shock; or (4) other relative contraindi-
cations to beta blockade (PR interval greater than
0.24 seconds, second- or third-degree heart block,
active asthma, or reactive airway disease). (Level of
Evidence: B)
2 Patients with early contraindications within the
fi rst 24 hours of STEMI should be reevaluated for
candidacy for beta-blocker therapy as secondary
prevention. (Level of Evidence: C)
3 Patients with moderate or severe LV failure should
receive beta-blocker therapy as secondary preven-
tion with a gradual titration scheme. (Level of Evi-
dence: B)

Class IIa
It is reasonable to administer an intravenous beta
blocker at the time of presentation to STEMI patients
who are hypertensive and who do not have any of
the following: (1) signs of heart failure; (2) evidence
of a low output state; (3) increased risk* for cardio-
genic shock; or (4) other relative contraindications
to beta blockade (PR interval greater than 0.24
seconds, second or third degree heart block, active
asthma or reactive airway disease). (Level of Evi-
dence: B)

Class III

Intravenous beta-blockers should not be adminis-

tered to STEMI patients who have any of the follow-

ing: (1) signs of heart failure; (2) evidence of a low

output state; (3) increased risk* for cardiogenic

shock; or (4) other relative contraindications to beta

blockade (PR interval greater than 0.24 seconds,

second or third degree heart block, active asthma or

reactive airway disease). (Level of Evidence: A)

f. Reperfusion

General concepts

See Table 3.2 for selection of reperfusion therapy.

Class I

1 STEMI patients presenting to a hospital with PCI

capability should be treated with primary PCI within

90 minutes of fi rst medical contact (see Figure 3.4)

as a systems goal. (Level of Evidence: A)

2 STEMI patients presenting to a hospital without

PCI capability and who cannot be transferred to a

PCI center and undergo PCI within 90 minutes of

fi rst medical contact (see Figure 3.1) should be

treated with fi brinolytic therapy within 30 minutes

of hospital presentation as a systems goal unless

fi brinolytic therapy is contraindicated. (Level of Evi-

dence: B)

Pharmacological reperfusion

See Figure 3.4 [12,13].

Indications for fi brinolytic therapy

Class I

1 In the absence of contraindications, fi brinolytic

therapy should be administered to STEMI patients

with symptom onset within the prior 12 hours and

ST elevation greater than 0.1 mV in at least two con-

tiguous precordial leads or at least 2 adjacent limb

leads. (Level of Evidence: A)

2 In the absence of contraindications, fi brinolytic

therapy should be administered to STEMI patients

with symptom onset within the prior 12 hours and new

or presumably new LBBB. (Level of Evidence: A)

Class IIa

1 In the absence of contraindications, it is reason-

able to administer fi brinolytic therapy to STEMI

patients with symptom onset within the prior 12

• Risk factors for cardiogenic shock (the greater the number of
  risk factors present, the higher the risk of developing cardio-
  genic shock) are age greater than 70 years, systolic blood pres-
  sure less than 120 mm Hg, sinus tachycardia greater than
  110 bpm or heart rate less than 60 bpm, and increased time
  since onset of symptoms of STEMI. IV indicates intravenous;
  LOE, level of evidence; LV, left ventricular; PCI, percutaneous
  coronary intervention; and STEMI, ST-elevation myocardial
  infarction.