Which Patients with Chest Pain to Admit to ICU?
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 I assume the question you are asking is not whether one can 
safely R/O MI or unstable angina in the ED and thus send the patient home 
but rather whether MI can be ruled-out with sufficient accuracy to allow 
low risk patients to be traiged to telemtry rather than ICU beds.  I'll 
address this latter question.

 A study done in 1985 and published in NEJM looked at the value of 
the initial ECG in predicting the risk of in-hospital complications in 
patients presenting with chest pain.  The goal was not necessarily to 
striclty segregate those with MI from those without but rather the more 
practicle goal of limiting ICU admissions to those patients (with or 
without MI) who experienced complications or required an 'intervention.' 
Complications included the occurence of v fib, sustained or non-sustained 
v tach, conduction disturbances, pump failure, atrial arrythmias or 
recurrent chest pain. Interventions included the need for carioversion, 
temporary pacing, hemodynamic monitoring or IABP.  It was hypothesized 
that, in the absence of the need for one of these interventions or the 
occcurance of complications, patients could be safely managed in a 
telemetry setting rather than an ICU bed.

 To this end they looked at the _initial_ ECG done in the ED. For 
purposes o this analysis an ECG was considered negative if 1) it was 
normal 2) showed nonspecific ST and T wave changes or 3) was unchanged 
from a previous ECG.  An ECG was considered to be positive if 1) showed 
pathologic Q waves 2) LVH 3) LBBB 4) paced rhythym or 5) had ST segemnt 
or T wave changes consistant with ischemia, infarction or strain.

 The following is a comparison of the rate of complications and 
need for interventions in the two groups:

    +ECG	-ECG	

MI				57%	15%
Life threatening complication	14%	0.6%
Sustained VT			6%	0.6%
Unsustained VT			15.2%	2.4%
Conduction Disturbance		8.3%	0.6%
Pump Failure			19.2%	4.2%
Atrial Arrth			11.9%	1.2%
Recurrent Chest Pain		27.2%	7.8%
VF				6%	0%
Death				9.9%	0%

Cardioversion			4.6% 	0.6%
Pacemaker			6.0%	0.6%
Hemodyamic Monitoring		18.2%	4.2%
IABP				3.0%	0.6%


 Thus the authors concluded that the need for an ICU as opposed to 
a telemtry bed could be predicted with reaonable accuracy not by totally 
excluding the posssibilty of AMI but rather of looking at the _need_ for 
an ICU bed based upon complications and need for interventions.


H. Louzon MD


(1) Brush et.al.  Use of the Initial Electrocardiogram to Predict 
In-Hospital Complications of Acute Myocardial Infarction.  NEJM 
1985;312:1137-1141