IAM_CON_SUPRA_DEL_ST_ACEP_2004 - Verónica Bernal

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CARDIOLOGY/SPECIAL CONTRIBUTION
2004 American College of Cardiology/American Heart
Association Guidelines for the Management of Patients With
ST-Elevation Myocardial Infarction: Implications for
Emergency Department Practice
Charles V. Pollack, Jr., MD, MA
Deborah B. Diercks, MD
Matthew T. Roe, MD, MHS
Eric D. Peterson, MD, MPH
From the Pennsylvania Hospital, University of Pennsylvania Health System, Philadelphia,
PA (Pollack); University of California at Davis, Sacramento, CA (Diercks); and Duke
Clinical Research Institute, Duke University School of Medicine, Durham, NC (Roe,
Peterson).
The American College of Cardiology and the American Heart Association last published evidence-
based guidelines for the management of ST-segment elevation myocardial infarction (STEMI) in
1999. In mid-2004, in recognition of the evolution and improvement of many of the most basic
tenets of clinical management of STEMI since that time, an updated edition of the STEMI guidelines
has been published. These guidelines offer many evidence-based recommendations that are
pertinent to the out-of-hospital and emergency department care of STEMI patients, including initial
evaluation, risk stratification, stabilizing management, and the choice between pharmacologic
and mechanical revascularization. These are presented and discussed here. [Ann Emerg Med.
2005;45:363-376.]
0196-0644/$-see front matter
Copyright ª 2005 by the American College of Emergency Physicians.
doi:10.1016/j.annemergmed.2004.11.003
INTRODUCTION
The American College of Cardiology (ACC) and the
American Heart Association (AHA) have jointly published
practice guidelines for various aspects of cardiovascular disease
since 1980. In 1990, the ACC and AHA published their first
document on ST-segment elevation myocardial infarction
(STEMI) management, entitled ‘‘Guidelines for the Early
Management of Patients with Acute Myocardial Infarction.’’1
This article was updated in 1996,2 using then for the first time
the term ‘‘acute coronary syndromes’’ to describe the spectrum
of unstable angina, non-STEMI and STEMI categories based
on initial ECG and serum biomarkers of myocardial necrosis.
These guidelines were further updated in electronic format in
1999.3 Separate guidelines have subsequently been published
for the evaluation and management of patients with non–ST-
segment elevation acute coronary syndrome in 20004-6 and
2002.7,8 In 2004, the ACC/AHA released their most recent
update of STEMI care.9 This 211-page document is complex
but authoritative, reflecting the many clinical studies performed
in this area since 1999. Our goal is to provide a condensed
summary of new or changed recommendations for STEMI care
that have direct pertinence to the emergency physician. These
fall into 4 areas: out-of-hospital, initial emergency department
(ED) evaluation and management, stabilizing management in
the ED, and reperfusion therapy.
Volume 45, no. 4 : April 2005
EVIDENCE CLASSIFICATIONS
Evidence used in developing recommendations in the
guidelines was classified as follows:
d Class I: There is evidence or general agreement that a specific
procedure or treatment is useful and effective.
d Class II: There is conflicting evidence or divergence of
opinion about the utility or efficacy of a procedure or
treatment.
d Class IIa: The weight of the evidence/opinion is in
favor of utility/efficacy.
d Class IIb: Utility/efficacy is less well established by
evidence/opinion.
d Class III: There is evidence or general agreement that
a specific procedure or treatment is neither useful nor
effective and may be harmful in some cases.
Recommendations made in the guidelines were based on
expert analyses of published data. The weight of the evidence was
then ranked according to the aggregate source(s) of those data:
d A (Highest): The data were derived from multiple
randomized clinical trials that involved large numbers of
patients.
d B (Intermediate): The data were derived from a limited
number of randomized trials that involved small numbers of
patients, or from analysis of nonrandomized studies or
observational registries.
Annals of Emergency Medicine 363
STEMI Guidelines Pollack et al
d C (Lowest): The primary basis for the recommendation is
expert opinion.
Thus, each recommendation made in the guidelines is cited
as Class I, II, or III (reflecting the task force’s analysis of
evidence) and weighted as A, B, or C (reflecting the quality and
extent of the evidence that was analyzed).
ED-PERTINENT CHANGES IN GUIDELINE
RECOMMENDATIONS
Recommendations from the guidelines that have direct
pertinence to the out-of-hospital and ED care of patients with
STEMI, and are new or significantly changed from the 1999
guidelines, are summarized in Table 1. They fall into the broad
categories of out-of-hospital care, initial ED evaluation and
management, stabilizing management in the ED, and reperfu-
sion therapy.
Out-of-Hospital Care
Nitroglycerin dosing. The 2004 STEMI guidelines suggest
a significant change in standard dosing for nitroglycerin to
patients with chest pain in the out-of-hospital setting. There is
a I-C recommendation that patients call 911 if anginal
symptoms are unimproved or worsening 5 minutes after 1
nitroglycerin tablet.9 The task force modified the traditional
recommendation of awaiting the results of up to 3 nitroglycerin
doses because self-treatment has often been cited as a cause of
delay in seeking treatment among patients with STEMI.10,11
Patient transport method. Consistent with advice usually
given to patients with chest pain by ED personnel, the
guidelines include a I-B recommendation that patients with
anginal symptoms be transported to the ED by ambulance
rather than by private automobile.9 In large registry experience,
just over half of STEMI patients are transported by
ambulance,12 providing those patients an opportunity for earlier
monitoring, initiation of medical management, and defibrilla-
tion (if indicated) that is not available to patients who have
friends or family transport them to the hospital.
Management during transport. The 2004 guidelines offer
a potentially expanded and important role for emergency
medical services (EMS) personnel. There are several recom-
mendations that are pertinent to emergency physicians with
medical control responsibilities for EMS. There is a I-A
recommendation that all EMS first responders be trained and
equipped to provide early defibrillation, as well as a I-B
recommendation that all public safety first responders be
trained and equipped to use automatic external defibrillators.9
Large studies have demonstrated the effectiveness of this
approach.13-17 In their discussion of optimal EMS response, the
task force indicates a preference for all-advanced life support
systems, even noting that when available, they may be more
cost-effective than a 2-unit (basic and then all-advanced life
support) response.18
There is a I-C recommendation that EMS providers
administer 162 to 325 mg of aspirin to be chewed by patients
suspected of having STEMI, unless contraindicated or already
364 Annals of Emergency Medicine
taken by the patient.9,19 If possible, it is then recommended
(IIa-B) that a 12-lead ECG be performed in the field.9 This
second recommendation requires training and equipment but is
aimed at guiding further EMS management and selection of
destination.20 Armed with this information, EMS personnel
should subject patients with ECG evidence of STEMI to
a ‘‘reperfusion checklist’’ (I-C) to assess comorbid and
underlying medical conditions that may affect eligibility for
fibrinolytic therapy and for signs of cardiogenic shock, which
may prompt redirection of patient transport to a facility with
capability for primary percutaneous coronary intervention in
STEMI patients.9 Figure 1 shows the primary components of
a ‘‘reperfusion checklist.’’
The task force recommends (IIa-B) that establishment of an
out-of-hospital fibrinolysis protocol is reasonable in settings in
which physicians are present in the ambulanceor in well-
organized EMS systems with full-time paramedics who have:
d 12-lead field ECGs with transmission capability
d initial and ongoing training in ECG interpretation and
STEMI treatment
d online medical control
d a medical director with training and experience in STEMI
management
d an ongoing continuous quality improvement program.4
Balancing the advantages (namely speed) and risks (mis-
diagnosis, missed contraindications, ability to manage compli-
cations) of out-of-hospital fibrinolysis is difficult. Studies
suggest that time saved in the first 1 to 2 hours after symptom
onset has greater prognostic benefit than time saved later in the
course of STEMI.21-28 Although individual trials have not
revealed a reduction in mortality with fibrinolysis, a meta-
analysis showed a 17% relative improvement compared with
inhospital lysis.29 Well-equipped and well-trained EMS systems
show excellent outcomes with fibrinolysis, comparable even to
direct primary percutaneous coronary intervention.30,31 Pro-
longed EMS transport time in rural settings provides the most
likely scenario in which the potential for an even greater relative
benefit from fibrinolysis may be derived, although rural EMS
systems may find it economically challenging to meet the
staffing and training criteria listed above.32
Beyond therapy, the guidelines also discuss the concepts of
in-the-field triage of STEMI patients and selective transfer
policies. Specifically, the task force states that each EMS system
should develop a written, consensus-based protocol for their
community to guide the triage of specific types of STEMI
patients personalized for their community’s transport logistics
and available facilities.9 Although in general patients suspected
of having STEMI should be taken to the nearest appropriate
facility, there are 2 clear exceptions: (1) patients younger than
75 years and with STEMI and cardiogenic shock should be
transported immediately or secondarily transferred to facilities
capable of primary percutaneous coronary intervention if it can
be performed within 18 hours of shock onset (I-A); and (2)
patients with STEMI and contraindications to lytic therapy
Volume 45, no. 4 : April 2005
Pollack et al STEMI Guidelines
Table 1. Summary of key new and updated recommendations in 2004 STEMI guidelines4 for out-of-hospital and ED care.*
Category
Recommended
Class
Recommended
Weight Recommendation
Out-of-hospital care I B Ambulance transport preferable to private automobile.
I C New guidelines for dosing nitroglycerin.
I A All EMS providers should have early defibrillation capability.
I C ASA 162–325 mg (chewed) should be provided to all patients suspected of
having STEMI.
IIa B 12-Lead ECG should be performed and evaluated out-of-hospital when available.
I C If 12-lead ECG shows STEMI, ‘‘reperfusion checklist’’ results should be relayed to
medical control.
IIa B Establishment of out-of-hospital fibrinolysis protocol is reasonable under specific
circumstances.
I A STEMI patients\75 y and with cardiogenic shock should be preferentially
transported to facilities with interventional capability.
I B STEMI patients with contraindications to lysis should be preferentially
transported to facilities with interventional capability.
IIa B STEMI patientsO75 y and with cardiogenic shock or severe CHF should be
preferentially transported (or transferred within 18 hours) to facilities with
interventional capability.
Initial ED evaluation
and management
I B Hospitals should have multidisciplinary teams and protocol-driven approach to
STEMI.
I B Door-to-treatment times for STEMI should be\30 min for lysis or\90 min to
balloon inflation.
I C ‘‘The choice of initial STEMI treatment should be made by the emergency
physician on duty.’’
I C Targeted medical history and physical examination should be promptly performed
in the ED; laboratory examinations should not delay reperfusion therapy.
I C ED door-to-initial-ECG time should be\10 min, and serial ECGs at 5- to 10-min
intervals may be appropriate if symptoms persist.
I B If ECG shows inferior STEMI, right-sided ECG should be obtained to screen for RV
infarction.
I C Reperfusion therapy is not dependent on biomarker assays.
IIa B Bedside echocardiography may be used to clarify the diagnosis of STEMI if it is
confounded by LBBB or when there is suspicion of posterior STEMI.
Stabilizing medical
management
III B Nitrates should not be given to patients who have received a PDE inhibitor within
past 24–48 h.
I A Oral b-blocker therapy should be administered immediately to patients without
contraindications.
IIa C Clopidogrel can be substituted for ASA in patients receiving lysis if allergic or
sensitive to ASA.
I B-C Patients undergoing reperfusion should receive UFH.
IIb B LMWH may be an acceptable alternative to UFH in patients undergoing lysis if
\75 y and if normal renal function.
III B LMWH should not be administered to STEMI patients who areO75 y or have
serum creatinineO2.5 mg/dL in men orO2 mg/dL in women.
IIa B Bivalirudin may be used as a heparin substitute if patient has known or suspected
HIT and is receiving lysis with streptokinase.
IIa B-C A platelet GP IIb/IIIa inhibitor should be started as soon as possible before
primary percutaneous coronary intervention for STEMI.
Reperfusion therapy I A If PCI not available within 90 min of ED arrival, lysis should be initiated unless
contraindicated.
I A Qualifying findings for lysis: STEMI with ST elevationO0.1 mV in appropriate
leads (or new/presumably new LBBB) and symptom onset\12 h.
IIa C Lytic therapy is appropriate for true posterior MI if symptom onset\12 h.
IIa B Lytic therapy is appropriate for STEMI with symptoms 12–24 h and continuing,
if ECG criteria met.
III C Lytic therapy is inappropriate in STEMI if symptom onsetO24 h.
IIb A-B-C Abciximab+half-dose tenecteplase or reteplase may be considered for prevention
of reinfarction (see text for further elucidation).
III B Abciximab+half-dose tenecteplase or reteplase should not be given to STEMI
patientsO75 y.
Volume 45, no. 4 : April 2005 Annals of Emergency Medicine 365
STEMI Guidelines Pollack et al
Table 1 (continued).
Category
Recommended
Class
Recommended
Weight Recommendation
I A Primary PCI by experienced operator in a timely fashion (\12 h symptoms,
\90 min after arrival) is preferred management for STEMI (see text for further
elucidation).
I C Primary PCI should be performed in lytic-ineligible patients who present with
STEMI and symptom onset between 12 and 24 h prior plus severe CHF,
hemodynamic or electrical instability, or persistent ischemic symptoms.
IIb B Facilitated PCI may be appropriate in higher-risk patients when PCI is not
immediately available and bleeding risk is low.
ASA, Aspirin; lysis, fibrinolytic therapy; CHF, congestive heart failure; RV, right ventricle; LBBB, left bundle-branch block; PDE, phosphodiesterase; UFH,
unfractionated heparin; LMWH, low-molecular-weight heparin; HIT, heparin-induced thrombocytopenia; GP IIb/IIIa, glycoprotein IIb/IIIa platelet receptor; PCI,
percutaneous coronary intervention; MI, myocardial infarction.
*See text for definition of ‘‘class’’ and ‘‘weight’’ for recommendations.
(optimally identified by the ‘‘checklist’’ [Figure 1]) should be
transported immediately or secondarily transferred within 30
minutes to a center capable of primary percutaneous coronary
intervention (I-B).9 Prompt catheterization and revasculariza-
tion in these situations have been demonstrated to improve 1-
year survival in STEMI patients with shock, with the clearest
benefit accruing to younger patients.33 Beyond these clear-cut
exceptions, selective referral to ACS ‘‘centers of excellence’’ with
full revascularization capacities and proven use of evidence-
based therapies has been proposed, but awaits further
validation.34-36
Emergency medicine bottom line. Patient education about
cardiac risk is the responsibility of all physicians. The ED ‘‘chest
pain visit’’ offers a ‘‘teachable moment’’during which patients
may be particularly receptive to guidance about self-evaluation,
self-treatment, and need for early presentation and choice of
transportation to the ED. The new dosing recommendation for
nitroglycerin to be applied before a 911 call should be
incorporated into patient teaching.
Out-of-hospital chest pain management is growing in-
creasingly sophisticated, providing new potential roles for EMS
staff and emergency and medical control physicians. Imple-
mentation of these guidelines to a given community, however,
will require specific tailoring to correspond to the skills of EMS
personnel, the availability of ‘‘centers of excellence,’’ the relative
transport times to these centers versus alternative hospitals, and
the skills of staff at these centers.
The need to minimize time to reperfusion and other
evidence-based therapies is a growing issue in the care of these
patients and is driving a move toward selective triage and
referral of patients with myocardial infarction. However, EMS
personnel and emergency and cardiology physicians will need to
work together to identify the most ‘‘appropriate strategy’’ for
a given location. The current guidelines should facilitate
pushing the argument for establishing capability-driven desti-
nation protocols for STEMI patients, especially those for whom
diagnostic confirmation is available through a 12-lead ECG and
366 Annals of Emergency Medicine
those with circulatory compromise. According to these
guidelines, ‘‘direct transport to a facility capable of rapid
revascularization is strongly preferred [italics added] to
interhospital transfer.’’
Initial ED Evaluation and Management
Protocols. Consistent with previous guidelines and sub-
sequent algorithms, the 2004 STEMI guidelines place signif-
icant emphasis on time to treatment, beginning at ‘‘first medical
contact,’’ thereby including out-of-hospital care. There is a I-B
recommendation that each hospital establish a multidisciplinary
team (inclusive of primary care physicians, emergency physi-
cians, cardiologists, nurses, and laboratory personnel) to develop
evidence-based and institution-specific protocols for the
evaluation and treatment of patients with chest pain suggestive
of STEMI.9 Such structured, prospectively directed care results
in improved clinical and economic outcomes.37
Evaluation. There is specific guidance given for time
parameters pertinent to the execution of chest pain protocols.
The delay between contact with the health care system (whether
EMS or ED) and initiation of fibrinolytic therapy should be less
than 30 minutes (I-B) or between contact and percutaneous
coronary intervention balloon inflation should be less than 90
minutes (I-B).9 The initial ECG should be obtained within 10
minutes of arrival, and the decision between lysis and
percutaneous coronary intervention should be made during the
ensuing 10 minutes.9,38 The task force recommends (I-C) serial
(every 5 to 10 minutes) ECGs or continuous ST-segment
monitoring for symptomatic patients whose presentation is
consistent with STEMI if the initial ECG is nondiagnostic.9
Mortality increases with the number of leads showing
ST-segment elevation.39
If the ECG shows evidence of an inferior wall STEMI, the
guidelines recommend (I-B) obtaining a right-sided ECG to
screen for right ventricular infarction.9 Isolated posterior
myocardial infarction should also be considered in those
presenting with ST depression in the anterior and precordial
Volume 45, no. 4 : April 2005
Pollack et al STEMI Guidelines
leads. The presence of a left bundle-branch block, especially in
a patient for whom no recent previous ECG tracings are
available, is frequently a confounder in the prompt diagnosis of
STEMI. In situations of left bundle-branch block and other less
readily interpretable ECGs (paced rhythms, left ventricular
hypertrophy that may obscure ST-segment changes) and
uncertainty of diagnosis, echocardiography or diagnostic
angiography may be used to clarify the diagnosis when these can
be obtained rapidly.21 This approach is to be preferred to
empiric fibrinolytic therapy.
Once the ECG is obtained, a brief, targeted medical history
should elicit previous cardiac history and risk factors, comorbid
conditions, risk of differential diagnostic considerations (espe-
cially aortic dissection), risk of bleeding, and signs of acute
cerebrovascular compromise. Physical examination should focus
on the ABCs, vital signs, central and peripheral perfusion, lung
and heart auscultation, and neurologic status.
Laboratory and imaging studies should be performed in the
assessment of patients with suspected STEMI but should not
delay definitive management. Reperfusion therapy is not
dependent on biomarker assays. Many STEMI patients, owing
to the release kinetics of serum biomarkers of myocardial
necrosis, will in fact have normal troponin and creatine kinase–
MB levels at presentation.40,41 A portable chest radiograph
should be obtained generally in STEMI patients but should not
delay reperfusion therapy unless it is being used to evaluate
1. Symptoms of STEMI
d Chest discomfort or related symptomsO15 min and
\12 h (if yes, proceed)
2. Contraindications to fibrinolytic therapy?
d Systolic blood pressureO180 mm Hg
d Diastolic blood pressureO110 mm Hg
d Right- vs left-arm systolic blood pressure difference
O15 mm Hg
d History of structural central nervous system lesion
(eg, AVM, tumor)
d Significant head/facial injury within past 3 mo
d Major surgery or gastrointestinal/genitourinary
bleeding within past 6 wk
d History of coagulopathy or taking warfarin
d CPRO10 min
d Pregnant female
d Serious systemic (eg, malignancy, hepatic, renal)
disease (if any yes, fibrinolysis may be
contraindicated)
3. Condition that makes primary percutaneous coronary
intervention preferable approach?
d Pulmonary edema (rales greater than halfway up)
d Hypotension (if yes, primary percutaneous coronary
intervention may be preferable approach, if available)
Figure 1. Components of ‘‘reperfusion checklist,’’
based on 2004 STEMI guidelines.4 AVM, Arteriovenous
malformation; CPR, cardiopulmonary resuscitation.
Volume 45, no. 4 : April 2005
suspected aortic dissection (I-C).9 If aortic dissection is
suspected, transthoracic or transesophageal echocardiography,
or computed tomography or magnetic resonance imaging,
should be used to differentiate between STEMI and aortic
dissection (I-B).9
The guidelines also suggest (IIa-B) that bedside transthoracic
echocardiography can be used to clarify the diagnosis of STEMI
if ECG interpretation in a ‘‘suspicious’’ patient is limited by left
bundle-branch block or pacing.9 Although validated,42 in many
EDs this resource is rarely available quickly. Nuclear perfusion
imaging, in contrast, receives a III-B (negative) recommenda-
tion, largely because of the time involved to obtain images.9
Emergency medicine bottom line. Time is of the essence in the
evaluation and treatment of STEMI patients in the ED. Best
results can be expected when all caregivers function along
a preset care pathway that prompts immediate diagnostic
evaluation, multidisciplinary input, and rapid care directed
dually by risk stratification of the patient and the capabilities of
the hospital. It is especially important to note that the guidelines
recommend reperfusion therapy on a timetable initiated at ‘‘first
medical contact,’’ which may differ from ED arrival time, and
which further emphasizes the importance of prompt and
efficient out-of-hospital care and transport. Emergency physi-
cians who work in noninterventional hospitals would be well
advised to work toward the development of standing, on-
demand transfer protocols for STEMI patients to nearby
institutions with direct percutaneous coronary intervention
capability.43 Focused medical history, physical, and ancillary
evaluation of the patient should be pursued with the sole intent
of facilitating prompt revascularization (regardless of manage-
ment strategy) and minimizing the likelihood ofencountering
complications of that care.
Stabilizing Medical Management in the ED
The basics. There are many medications that are recom-
mended in the emergency treatment of patients with STEMI.
Often these are appropriate for consideration while the patient
is still in the ED. Aspirin (162 [I-A] to 325 [I-C] mg) should be
administered either out-of-hospital or immediately on ED
arrival, unless the patient has an aspirin allergy, in which case
clopidogrel is indicated as an alternative before lytic therapy
(IIa-C).9 Oxygen should be given to patients with pulse
oximetry readings below 90% (I-B) and perhaps to all STEMI
patients during the first 6 hours of care (IIa-C).9 Patients with
hemodynamic compromise or frank pulmonary edema may
require noninvasive positive-pressure ventilatory support or
intubation and mechanical ventilation to achieve satisfactory
oxygenation.44
Nitroglycerin. Sublingual nitroglycerin (0.4 mg) is indicated
for patients with ongoing ischemic discomfort, treatment of
hypertension, or management of pulmonary vascular conges-
tion, given every 5 minutes for 3 doses, after which intravenous
nitroglycerin should be considered (I-C).9 Because nitroglycerin
reduces both preload and afterload, it should not be given
(III-C) to patients with systolic blood pressure less than
Annals of Emergency Medicine 367
STEMI Guidelines Pollack et al
90 mm Hg or more than 30 mm Hg below baseline, to patients
with pulse rates below 50 beats/min or above 100 beats/min, or
to patients with suspected right ventricular infarction.9 There
are minimal data to support a mortality benefit from nitrate
therapy.45 Patients taking phosphodiesterase inhibitors for
erectile dysfunction should not be given nitroglycerin if they
have received a phosphodiesterase inhibitor within 24 hours (48
hours if using tadalafil [Cialis]). Phosphodiesterase inhibitors
potentiate the hypotensive effects of nitrates.46 The history of
phosphodiesterase inhibitor use may be obscure and requires
directed questioning, even in patients who may appear too
young (or too female) to have been prescribed one of these
agents.
Morphine. Intravenous morphine sulfate (2 to 4 mg
intravenous, then 2 to 8 mg intravenous at 5- to 15-minute
intervals) is the analgesic of choice (I-C) for STEMI pain.9
Nitroglycerine, b-blockers, and oxygen all also contribute to
analgesia in STEMI patients, but morphine sulfate may still be
required. Morphine sulfate also works as an anxiolytic and as
a venodilator in pulmonary vascular beds. There have been no
studies, however, indicating a mortality benefit from morphine
sulfate use.
b-Blockers. Oral b-adrenergic blockers should be adminis-
tered promptly to all patients without contraindications (I-A).9
b-Blockers clearly reduce myocardial oxygen demand during
the first few hours after onset of STEMI and may further
augment myocardial perfusion by extending the time in the
cardiac cycle spent in diastole. Establishment of a mortality
advantage from b-blocker therapy has, however, been difficult,
with some studies showing benefit47,48 and some showing
none.49-52 b-Blockers can be given intravenously to patients
without contraindications, particularly if they have tachycardia
or hypertension (IIa-B).9 b-Blockers should not be given to
STEMI patients with:
d pulse rate less than 60 beats/min
d systolic blood pressure less than 100 mm Hg
d evidence of moderate or severe left ventricular failure
d signs of peripheral hypoperfusion
d ECG PR interval longer than 0.24 seconds
d second- or third-degree atrioventricular block
d active asthma or reactive airway disease, with active
bronchospasm
d infarction precipitated by cocaine use (because this would
allow unopposed a-adrenergic stimulation)
Anticoagulation. Activation of the coagulation cascade is an
integral component of STEMI pathophysiology. The 2004
guidelines recommend the use of unfractionated heparin in
STEMI patients regardless of revascularization strategy with a
I-C rating.9 A small mortality benefit has been attributed to
unfractionated heparin use in patients managed with lytic
agents.53 Specifically, a bolus of 60 U/kg (maximum 4,000 U)
of unfractionated heparin followed by an infusion of 12 U/kg
per hour (maximum 1,000 U/h) is recommended in STEMI
patients receiving alteplase, reteplase, or tenecteplase (I-C).9 The
activated partial thromboplastin time in these patients should be
368 Annals of Emergency Medicine
maintained at 1.5 to 2 times control (50 to 70 seconds).
Further, unfractionated heparin should be given to patients
receiving nonselective fibrinolytic agents (streptokinase, anis-
treplase, urokinase) if they are at high risk for systemic emboli
(I-B) or to patients receiving streptokinase regardless (IIb-B).9
The different levels of support for unfractionated heparin derive
from the recognition that the nonspecific lytic agents produce
a systemic coagulopathy and are themselves anticoagulants,
whereas the more fibrin-specific agents are either procoagulants
or induce little systemic anticoagulation.54-56
In patients treated with primary percutaneous coronary
intervention, weight-adjusted boluses of unfractionated heparin
of 70 to 100 U/kg are recommended by the task force, with the
goal of maintaining an activated clotting time in the
catheterization laboratory of 250 to 350 seconds.9 The initial
bolus-infusion regimen described above is appropriate for ED
anticoagulation of the STEMI patient before percutaneous
coronary intervention. Cardiologists may choose to reduce
heparin doses if platelet glycoprotein IIb/IIIa receptor antago-
nists are being used. A baseline platelet count should be
obtained in the ED before unfractionated heparin is adminis-
tered to assist in subsequent monitoring for heparin-induced
thrombocytopenia.57
Alternative anticoagulants, namely, the low-molecular-
weight heparins and direct antithrombins, receive less specific
support in these guidelines. There is a IIb-B recommendation in
favor of a low-molecular-weight heparin in patients younger
than 75 years, with normal renal function (serum creatinine
level\2.5 mg/dL in men or\2.0 mg/dL in women), who are
receiving lytic therapy.9 Enoxaparin, used with full-dose
tenecteplase, is the best-studied regimen in this regard; in the
Assessment of the Safety and Efficacy of a New Thrombolytic
Regimen (ASSENT)-3 trial, patients younger than 75 years
who received this combination had lower rates of 30-day
mortality, inhospital reinfarction, and inhospital recurrent
ischemia than did patients who received unfractionated
heparin and tenecteplase.58 This difference was not maintained
at 1-year follow-up. There are 2 class III recommendations
about low-molecular-weight heparins in STEMI: they should
not be administered to patients older than 75 years if
receiving lytics (weight of evidence, B), and they should
not be given to patients with significant renal dysfunction,
regardless of age (B)9 (Table 2).
The direct antithrombin agent bivalirudin is recommended
in the 2004 guidelines only as an alternative to unfractionated
heparin in patients receiving streptokinase, who are known to
have a history of heparin-induced thrombocytopenia (IIa-B).9
Advanced antiplatelet therapy in patients going to percutaneous
coronary intervention. The glycoprotein IIb/IIIa agents are
discussed in an ED-pertinent context only in a limited fashion
in the 2004 STEMI guidelines. There are recommendations to
initiate abciximab ‘‘as early as possible’’ before percutaneous
coronary intervention (IIa-B) or eptifibatide or tirofiban
‘‘before’’ percutaneous coronary intervention (IIb-C) in STEMI
patients.9 Patients in the Abciximab before Direct Angioplasty
Volume 45, no. 4 : April 2005
Pollack et al STEMI Guidelines
Table 2. Pharmacologic therapy for various reperfusion strategies for STEMI, based on 2004 guidelines.4*
Strategy Primary Agent Anticoagulant Antiplatelet Agents
Fibrinolysis Streptokinase or
anistreplase
UFH bolus 60 U/kg (max 4,000 U), then infusion
12 U/kg/h (max 1,000U/h) to keep APTT
1.5 to 2 times control (IIb-B); bivalirudin if
documented history of HIT (IIa-B)
No recommendations
Reteplase UFH as above Half-dose reteplase+abciximab if anterior MI,
age\75 y, and no significant bleeding
risk (IIb-A and B)
Alteplase UFH as above Half-dose alteplase+abciximab as above
Tenecteplase UFH as above; enoxaparin 30 mg IV bolus and
1 mg/kg subcutaneously every 12 h if
age\75 y and normal renal function (IIb-B)
Half-dose tenecteplase+abciximab as above
Direct percutaneous
coronary intervention
UFH as above in ED; patient should then receive
weight-adjusted boluses of 70–100 U/kg to
maintain activated clotting time at 250–350 s
Abciximab ‘‘as early as possible’’ (IIa-B);
eptifibatide or tirofiban before PCI (IIb-C)
APTT, Activated partial thromboplastin time; IV, intravenous.
*Parenthetical notations refer to recommendations in guidelines.4
and Stenting in Myocardial Infarction Regarding Acute and
Long-Term Follow-up (ADMIRAL) study who received
abciximab showed composite benefit at 6 months after
STEMI,59 and the Controlled Abciximab and Device
Investigation to Lower Late Angioplasty Complications
(CADILLAC) study showed that abciximab added to the
benefit achieved in STEMI patients by percutaneous trans-
luminal coronary angioplasty alone, regardless of whether
a stent was used.60 The role of glycoprotein IIb/IIIa therapy in
patients treated with fibrinolysis is discussed below and is
summarized in Table 2.
Other pharmacologic agents. The guidelines address the use of
angiotensin-converting enzyme inhibitors (and angiotensin re-
ceptor blockers) in STEMI but make no recommendations other
than consideration of their use within the first 24 hours, relieving
the emergency physician of an evidence-based responsibility for
acutely prescribing them in the ED.9 There is no recommenda-
tion for the urgent use of statins in these guidelines.
Strict glucose control, using an insulin infusion if necessary,
is recommended for diabetic patients with STEMI (I-B).9
Documented magnesium deficits should be replenished,
especially in patients on diuretic therapy before the STEMI
(IIa-C), but in the absence of documented electrolyte derange-
ments or significant ventricular arrhythmias, magnesium should
not be given to STEMI patients (III-A).9 Patients with torsades-
de-pointes ventricular tachycardia associated with a prolonged
ECG QT interval should receive 1 to 2 g of magnesium
administered intravenously over a 5-minute period (IIa-C).61
Calcium channel blockade with verapamil or diltiazem is
indicated in STEMI patients in whom b-blockers are ineffective
or contraindicated, for relief of ischemic symptoms, or control
of rapid ventricular rate in the absence of congestive heart
failure, left ventricular dysfunction, or atrioventricular block
Volume 45, no. 4 : April 2005
(IIa-C).9 Verapamil should not be given to bradycardic
patients.62 Diltiazem exerts a detrimental mortality effect on
STEMI patients with diastolic dysfunction.63 Nifedipine should
not be given (III-B) to STEMI patients because of reflex
sympathetic activation, tachycardia, and hypotension.9
Emergency medicine bottom line. The emergency physician
should use a basic medical stabilization regimendincluding
oxygen and aspirin plus, where indicated, nitrates, morphine,
b-blockers, anticoagulants, and insulin for maintaining glucose
homeostasis in diabeticsdfor all STEMI patients. Clopidogrel
is recommended only as a substitute for aspirin in STEMI.
Calcium channel blockers and magnesium carry specific and
rather limited indications for ED use. An institutional protocol
that addresses specific issues in the further stabilization of
patients going directly to the catheterization laboratorydsuch
as reduction of anticoagulant doses and use of glycoprotein IIb/
IIIa agentsdshould be developed to facilitate the smooth
transition of care for the STEMI patient from the ED to the
laboratory. Again, there is no substitute for regular, prospective,
evidence-based discussions between emergency physicians and
cardiologists about plans to provide consistent, optimal STEMI
care in a given institution.
Reperfusion Therapy
General considerations. The 2004 guidelines clearly establish
the fundamental role of the emergency physician in determining
reperfusion strategy for patients with STEMI. In general,
STEMI patients presenting within 12 hours without contra-
indications should be considered for reperfusion therapy.
Reperfusion therapy can also be considered for patients
presenting between 12 to 24 hours under specific situations,
such as patients with ongoing symptoms and diagnostic ECG
changes.
Annals of Emergency Medicine 369
STEMI Guidelines Pollack et al
Compared with lytic therapy, direct percutaneous coronary
intervention is generally associated with lower short-term
mortality, less nonfatal reinfarction, and less hemorrhagic
stroke.64 This benefit, however, can be reasonably expected only
in centers with the capability to achieve rapid intervention (\90
minutes) and when performed by experienced personnel
(interventionist performingR75 primary percutaneous coronary
intervention procedures per year and working in a catheteriza-
tion laboratory that performsO200 percutaneous coronary
intervention procedures, with at least 36 being direct
percutaneous coronary intervention for STEMI per year).9
Strategies. The recommendations for the management of
STEMI patients are complex and differ by facility type.
Although well-conceived protocols are associated with a higher
likelihood of successful clinical outcomes, such protocols are not
typically inclusive of all possible scenarios, leaving the
emergency physician and his or her consultants to determine the
optimal approach to each patient, based on available resources.
STEMI patients presenting to a facility without the capability
for expert primary percutaneous coronary intervention within
90 minutes of first medical contact should undergo lytic therapy
unless contraindicated (I-A) (Figure 2).9 An alternative strategy
is to rapidly transfer reperfusion patients to an experienced
primary percutaneous coronary intervention center for primary
percutaneous coronary intervention within 90 minutes of
presentation. Although accumulating data continue to suggest
that percutaneous coronary intervention is the preferred
approach to STEMI in high-volume percutaneous coronary
intervention centers,65 the critical issue of time to restoration of
myocardial perfusion favors lysis over percutaneous coronary
intervention that is delayed for longer intervals. These issues of
time and transfer are major issues for rapid percutaneous
coronary intervention because only 20% of hospitals in the
United States have catheterization laboratories, and fewer still
have direct percutaneous coronary intervention capability.9
Reperfusion candidates presenting to an experienced percu-
taneous coronary intervention center should generally receive
percutaneous coronary intervention, assuming they can receive
this within 90 minutes. The exception to this rule is patients
presenting later (but within 3 hours) where fibrinolytic therapy
is the preferred therapy, unless rapid percutaneous coronary
intervention within 60 minutes is an option (Figure 3).
Fibrinolytic therapy for STEMI. Fibrinolytic therapy provides
a survival benefit for patients with STEMI.22,66-68 Mortality
reduction from lysis is greatest when therapy is given within the
first hour of symptom onset, and the benefit declines thereafter
by about 1.6 lives per 1,000 patients treated per 1-hour
delay.21,69 Patients older than 75 years face a high mortality risk
from STEMI with and without therapy; although the risk of
complications from lytic therapy is higher in this group than in
younger patients, the absolute number of lives saved per 100
patients treated is actually higher among older patients.70
The benefits of lytic therapy are proportional to the amount
of myocardium at risk and the rapidity of its initiation. Patients
with left bundle-branchblock or anterior ST-segment elevation
370 Annals of Emergency Medicine
have more myocardium at risk from their event and therefore
have the greatest potential benefit from lytic therapy.21 The
earlier therapy begins, the more likely the benefit, with the
greatest benefit accruing within the first 3 hours after symptom
onset and persisting through 12 hours. Beyond 12 hours,
fibrinolytic therapy should be reserved for those with persistent
symptoms and ST-segment elevation and no options for rapid
percutaneous coronary intervention. Fibrinolytic therapy is not
recommended (III-C) if initial symptoms began more than 24
hours before medical contact, nor is it recommended for
patients with ST-segment depression (III-A), unless true
posterior wall myocardial infarction is suspected.9
Figure 4 lists the absolute and relative contraindications to
the use of fibrinolytic therapy. Relative contraindications
assume more importance in patients with lower-risk STEMI,
such as hemodynamically stable inferior wall myocardial
infarction without right ventricular involvement.21 ‘‘Neurologic
contraindications,’’ any history of intracranial hemorrhage,
history of significant closed head or facial trauma or ischemic
stroke within 3 months, or uncontrolled hypertension are I-A
concerns cited specifically by the task force, and the guidelines
go on to recommend that STEMI patients at ‘‘substantial
(R4%) risk’’ of intracranial hemorrhage be treated with
percutaneous coronary intervention rather than lytics (I-A).9
Several models for estimating this risk exist,71-74 all of which
consider as primary parameters patient age, weight, and severity
of hypertension on admission.
The task force addresses a comparison among the lytic agents
in the guidelines’ discussion but does not make rated
recommendations. The specific choice of agent for lytic therapy
must account for efficacy, likelihood of complications (namely
intracranial hemorrhage), and cost. Streptokinase may be best
considered in patients at higher risk for stroke and from an
economic perspective, unless the patient has received it
previously or has other contraindications.75 Alteplase or
reteplase is most supported in younger patients who present
earlier or have a large area of injury, such as anterior myocardial
infarction; further, tenecteplase may be superior still because of
relatively fewer bleeding complications76 (Table 2).
Complications. Clinically important hemorrhagic complica-
tions of lytic therapy include intracranial hemorrhage and other
bleeding that may or may not require blood transfusion. The
small but finite risk of intracranial hemorrhage occurs mostly in
the first 24 hours after treatment.21 The guidelines suggest that
any change in neurologic status during or after a lytic regimen is
administered, particularly within that first day, be considered
intracranial hemorrhage until proven otherwise by a brain
imaging study, and all lytic, antiplatelet, and anticoagulant
therapies should be halted until that confirmation is obtained
(I-A).9 Typical initial features of intracranial hemorrhage include
change in level of alertness, focal neurologic abnormalities,
coma, seizure, and less specific signs such as headache, nausea,
and vomiting. If intracranial hemorrhage occurs, treatment may
include infusions of cryoprecipitate, fresh frozen plasma,
protamine, platelets, and mannitol; endotracheal intubation and
Volume 45, no. 4 : April 2005
Pollack et al STEMI Guidelines
Figure 2. STEMI management at centers with direct percutaneous coronary intervention capability (based on 2004 guidelines4);
details in text. DNR, Do-not-resuscitate order.
Figure 3. STEMI management at centers without direct percutaneous coronary intervention capability (based on 2004
guidelines4); details in text.
hyperventilation; and surgery (I-C and IIa-C).9 The 30-day
mortality rate from intracranial hemorrhage associated with lytic
therapy for STEMI may exceed two thirds.77,78
Failure to reperfuse is a complication of lytic therapy that is
sometimes apparent in the ED. Typical 90-minute patency rates
on patients who undergo angiography after lysis are 75% or less.
The guidelines state that the pattern of ST-segment elevation,
cardiac rhythm, and symptomatology of STEMI patients
should be closely monitored during 60 to 180 minutes after
initiation of lysis (IIa-B).9 A reduction of at least 50% of the
initial ST-segment elevation injury pattern should be detected
on a follow-up ECG 60 to 90 minutes after initiation of
therapy, and both electrical and hemodynamic stability should
be achieved and maintained. Persistence of symptoms, absence
of at least some normalization of ST-segments, or clinical
Volume 45, no. 4 : April 2005
instability generally characterizes failed lysis and constitutes
the need to consider rescue percutaneous coronary intervention,
which may require transfer to another institution if interven-
tional capability is not available at the primary treating
center.
Rescue (or ‘‘salvage’’) percutaneous coronary intervention,
defined as intervention within 12 hours after lysis in patients
with continuing or recurrent myocardial ischemia, has been
shown in a number of studies to restore patency and improve
clinical outcomes. Best results are likely obtained within 3 to 6
hours of symptom onset, however, leaving little time for
recognition of failure of the fibrinolytic approach. Given this
concern and the recognition that clinical markers of reperfusion
(eg, relief of pain, partial resolution of ST-segment elevation,
reperfusion arrhythmias) are not fully reliable in identifying
Annals of Emergency Medicine 371
STEMI Guidelines Pollack et al
successful lysis,9 the emergency physician may have to make
prompt decisions to transfer on the basis of limited data.
Combination fibrinolysis and glycoprotein IIb/IIIa inhibition.
The addition of advanced platelet inhibition to lytic therapy has
the potential to yield benefit additional to lysis alone;
glycoprotein IIb/IIIa therapy alone has not been shown to
improve rates of reperfusion in STEMI.79 At least 3 angiographic
studies have shown higher Thrombolysis in Myocardial In-
farction (TIMI)-3 flow rates at 60 to 90 minutes when
abciximab80,81 or eptifibatide82 is used in combination with
a 50% dose of a lytic agent. Other studies have shown
improvement in nonfatal reinfarction rates and other myocardial
infarction complications with glycoprotein IIb/IIIa agents.
However, combination therapy has not been shown to reduce
mortality relative to fibrinolysis alone.58,83 In addition, combi-
nation therapy led to excess bleeding risk, including stroke,
disproportionately in patients older than 75 years.58,83 The
guideline recommendations therefore give limited support to
adding abciximab to half-dose reteplase or tenecteplase for the
prevention of reinfarction (IIb-A) and other complications of
STEMI (IIb-B) if patients have anterior myocardial infarction,
are younger than 75 years, and have no undue bleeding risk.9
Combination therapy with lytics and glycoprotein IIb/IIIa agents
is not recommended (III-B) in patients older than 75 years.9
Direct percutaneous coronary intervention for STEMI. Percu-
taneous coronary intervention can be considered in up to 90%
of STEMI patients.64,84,85 Direct percutaneous coronary
Absolute contraindications
d Any previous intracerebral hemorrhage
d Known structural central nervous system lesion (eg,
AVM, tumor)
d Ischemic stroke within 3 mo unless acute ischemic
stroke of\3 h onset
d Significant closed head or facial injury within 3 mo
d Suspicion of aortic dissection
d Active bleeding (excluding menses) or bleeding
dyscrasia
Relative contraindications
d History of chronic, severe, and poorly controlled hyper-
tension, or severe (systolic blood pressureO180 mm Hg
or diastolicO110 mm Hg) hypertension on admission
d Traumatic or prolonged (O10 min) CPR or
noncompressible vascular punctures
d Major surgery or internal bleeding within 3–4 wk
d Other central nervous disease (structuralor dementia)
not noted above
d Pregnancy
d Active peptic ulcer disease
d Current use of anticoagulants (the higher the INR, the
higher the risk of bleeding)
d Previous exposure to or previous allergic reaction to
streptokinase or anistreplase, if using these agents
Figure 4. Absolute and relative contraindications to fibrino-
lytic therapy of STEMI (adapted from 2004 guidelines4). INR,
International normalized ratio.
372 Annals of Emergency Medicine
intervention may be appropriate for patients eligible for lytic
therapy and for those in whom the use of lytics is associated
with an unacceptably high risk of bleeding.86 The guideline
recommendations for direct percutaneous coronary intervention
are as follows:9
d Should be performed in STEMI patients who can undergo
percutaneous coronary intervention within 12 hours of
symptom onset, if in an appropriate setting (see below) (I-A),
with a goal of 90 minutes, door to balloon (I-B).
d If symptom duration is within 3 hours and the door-
to-balloon time (percutaneous coronary intervention) minus
the door-to-needle time (lytics) is less than 60 minutes,
percutaneous coronary intervention is preferred. If greater
than 60 minutes, lysis is preferred (I-B).
d If symptom duration is more than 3 hours, percutaneous
coronary intervention is preferred (I-B).
d Should be performed in STEMI patients younger than 75
years who develop shock within 36 hours of myocardial
infarction and are suitable for revascularization (I-A); in
patients with severe congestive heart failure with or
without pulmonary edema (I-B); and in patients older
than 75 years and with shock (IIa-B).
Time to reperfusion is every bit as important when the
percutaneous coronary intervention strategy is followed as it is
for lysis. At least 2 studies have clearly demonstrated a
relationship between increasing door-to-balloon times and
mortality.87,88 In fact, when lytic therapy and percutaneous
coronary intervention are compared, the strongest mortality
benefit of the interventional strategy exists when treatment
occurs within 60 minutes89; mortality increases with each
15-minute delay.90 In 2 head-to-head trials comparing these
approaches, percutaneous coronary intervention was superior to
lysis in the majority of patients when symptom duration was less
than 3 to 4 hours.31,91
For STEMI patients not eligible for lytic therapy, direct
percutaneous coronary intervention is recommended if symp-
tom duration is less than 12 hours (I-C) or if symptoms have
been present for 12 to 24 hours and the patient has severe CHF,
hemodynamic or electrical instability, or persistent ischemic
symptoms (IIa-C).9
The considerations given to redirecting some STEMI
patients to percutaneous coronary intervention–capable centers
from the EMS setting are based on limited experience92-94 with
emergency interhospital transfer for interventional reperfusion
rather than lytic therapy at the initial hospital. Unless an
EMS-level redirection is initiated when the patient first ‘‘enters
the system,’’ it is typically logistically difficult to arrange and
execute an interhospital transfer that allows a door-to-balloon
time versus door-to-needle time of 90 minutes or less.
Another approach to this issue is facilitated percutaneous
coronary intervention, in which the STEMI patient is treated
pharmacologically (with full-dose lysis or with half-dose lysis
with or without a glycoprotein IIb/IIIa blocker), with a planned
intervention to follow in short order. If bleeding risk is low,
facilitated percutaneous coronary intervention earns a IIb-B
Volume 45, no. 4 : April 2005
Pollack et al STEMI Guidelines
recommendation from the task force,9 which notes that, to date,
studies of facilitated percutaneous coronary intervention have
not demonstrated any consistent benefit in reducing infarct size
or improving outcomes.95-97
Emergency medicine bottom line. Reperfusion of ischemic and
infarcting myocardium is the primary goal of STEMI
management in the ED. If direct percutaneous coronary
intervention is not available at a given institution, current
recommendations for optimal care are to administer fibrinolytic
therapy (in the absence of contraindications). If patients have
contraindications to lysis, direct percutaneous coronary in-
tervention is strongly preferred over purely medical manage-
ment, even if that approach mandates emergency transport to
another facility. If direct percutaneous coronary intervention
is available and the door-to-balloon time can be kept to less
than 90 minutes, the interventional strategy is preferred; if
a delay is expected, facilitated percutaneous coronary in-
tervention might be a reasonable option. Adjunctive therapy
with glycoprotein IIb/IIIa agents or enoxaparin may be
considered in some cases but should only be given in
consultation with the treating cardiologist. Table 2 presents
a summary of the pharmacologic elements of various ‘‘reper-
fusion cocktails.’’
There is no substitute for the development and consistent
execution of a multidisciplinary pathway for STEMI manage-
ment in each ED, which maximizes the institution’s capabilities
and is consistent with the consulting cardiologists’ expertise and
preference. Having such a pathway on which to base time-
sensitive management in the ED can improve quality of care
and promote patient safety. The emergency physician plays
a critical role in hastening the reperfusion cycle by contributing
to the patient’s care via (1) rapid diagnosis; (2) risk assessment
and determination of indications for and contraindications to
different reperfusion strategies; (3) administration of fibrino-
lytics or rapid activation of the interventional team for
percutaneous coronary intervention; and (4) monitoring of the
success of lytic therapy and facilitation of referral to another
center if the patient fails to reperfuse or encounters mechanical
complications.
In summary, these ACC/AHA guidelines present the
cardiology specialty’s assessment of current best practice for the
diagnosis and management of STEMI. New or updated
recommendations in the 2004 guidelines that are pertinent to
the ED evaluation and treatment of these patients include
significant changes in approach to reperfusion therapy, even
starting potentially in the out-of-hospital setting. Figures 2 and
3 summarize a practical approach to the evidence-based
evaluation and treatment of STEMI patients.
Funding and support: All authors have received honoraria or
research support (direct or indirect) from Aventis Pharma-
ceuticals, Millennium Pharmaceuticals, Schering-Plough,
Bristol-Myers-Squibb, and Sanofi, which market therapeutic
agents cited in this article. Dr. Pollack has received honoraria
from Genentech.
Volume 45, no. 4 : April 2005
Publication dates: Received for publication September 2,
2004. Revision received October 15, 2004. Accepted for
publication November 1, 2004. Available online
February 12, 2005.
Reprints not available from the authors.
Address for correspondence: Charles V. Pollack, Jr., MD, MA,
Department of Emergency Medicine, Pennsylvania Hospital,
800 Spruce Street, Philadelphia, PA 19107; fax 610-687-
0137; E-mail pollackc@pahosp.com.
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Volume 45, no. 4 : April 2005
	2004 American College of Cardiology/American Heart Association Guidelines for the Management of Patients With ...
	Introduction
	Evidence classifications
	ED-pertinent changes in guideline recommendations
	Out-of-hospital care
	Initial ED evaluation and management
	Stabilizing medical management in the ED
	Reperfusion therapy
	References