Abnormal ECG
CHF
Suspicion of structural heart disease
Ischemic, dysrhythmic, obstructive, valvular
HCT <30
Shortness of Breath
Hypotension(SBP <90)
Family history of sudden cardiac death
Advanced age
Evidence of hemorrhage (occult blood)<unk>  without prodrome
Ischemic, dysrhythmic, obstructive, valvular
None of the above findings (esp if age <45)
No events on telemetry after period of observation (2-4 hours in the ED)
Consider referral for holter or til-table test
Syncope
Cardiovascular-mediated syncope
Laryngospasm
Dysrhythmias:
Chest pain 
WPW 
Sedation 
Long QT Syndrome/QT prolongation