use only for patients with ACS undergoing PCI.

� Anticoagulation

Administer either unfractionated heparin (UFH) or lowmolecular-weight heparin (LMWH) in all patients with

ACS and no known contraindications. LMWH ( enoxaparin)

is generally preferred given its more predictable weightbased onset of activity, reduced tendency for immunemediated thrombocytopenia, and lack of requirement for

laboratory monitoring. That said, the longer half-life and

lack of easy reversibility of LMWH is problematic in

patients for whom invasive interventions are planned.

UFH is typically recommended for patients undergoing

PCI, whereas LMWH is preferred for patients with UA/

NSTEMI who are not undergoing emergent reperfusion.

Fondaparinux and bivalirudin (a direct thrombin

inhibitor) are two of the newer anticoagulant agents a vailable for the management of patients with ACS and will

likely have an expanding role in the near future. Both have

been shown to be equally effective with fewer bleeding

complications as compared with standard treatment with

UFH or LMWH in select patient populations.

� Beta-Blockers

Beta-blockers exhibit antiarrhythmic, anti-ischemic, and

antihypertensive properties. They reduce myocardial 0 2

demand via decreasing the heart rate, cardiac afterload,

and ventricular contractility. Current guidelines recommend the initiation of treatment in all ACS patients with

no contraindications (decompensated CHF, hypotension,

heart blocks, and reactive airway disease). Metoprolol can

be given in 5-mg N doses every 5 minutes for a total of

3 doses or as a single 50-mg oral dose if N treatment is not

required.

� Reperfusion Therapy

Patients with STEM! require immediate reperfusion

therapy with either PCI or thrombolysis. The American

College of Cardiology guidelines recommend a duration

of no more than 90 minutes between patient presentation and balloon inflation in those undergoing PCI and a

duration of no more than 30 minutes between presentation and treatment in those undergoing thrombolysis.

PCI is the preferred modality owing to a decreased risk of

bleeding complications, lower incidence of recurrent

ischemia and infarction, and improved rates of survivability. For patients with UA or NSTEMI, an early invasive approach (within 24-48 hours) utilizing PCI reduces

the risk of death, AMI, and recurrent ACS. Thrombolysis

is not recommended for patients with either UA or

NSTEMI.

DISPOSITION

� Admission

Admit all patients with suspected ACS to a monitored bed

for serial ECG testing and cardiac marker analysis. Highrisk patients including those with elevated cardiac markers,

ischemic ECG changes, and refractive symptoms warrant

admission to a critical care setting for early PCI. STEM!

patients require admission to a critical care setting after

appropriate reperfusion therapy (PCI or thrombolysis).

� Discharge

Patients at a very low risk for ACS (young healthy patient,

atypical history, normal ECG, and negative serial cardiac

markers) who remain symptom free during an emergency

department observation period of several hours can be

safely discharged home with early stress testing arranged in

the outpatient setting.

CHAPTER 14

SUGGESTED READING

Green G, Hill P. Chest pain: Cardiac or not. In: Tintinalli JE,

Stapczynski JS, Ma OJ, Cline DM, Cydulka RK, Meckler GD.