ECG
History and physical exam
Look for intoxication/withdrawal, infection, dehydration, bleeding, or a psychiatric/emotional<unk> ate
Consider orthostatic vital signs
If history and physical are unable to explain the<unk> , limited labs and imaging<unk> udies may be indicated:
CBC
BMP
Utox
Urine pregnancy
Consider:
Empiric treatment for anxiety or pain (e.g. benzodiazepine or NSAID)
Urinalysis
TSH
Troponin
CXR
Consider workup for PE (e.g. D-dimer or CTA)
Look for intoxication/withdrawal, infection, dehydration, bleeding, or a psychiatric/emotional<unk> ate
CBC
BMP
Utox
Urine pregnancy
Empiric treatment for anxiety or pain (e.g. benzodiazepine or NSAID)
Urinalysis
TSH
Troponin
CXR
Consider workup for PE (e.g. D-dimer or CTA)
Based on ECG
Look for regular rate and presence of p-waves to support diagnosis of<unk> 
Look for regular rate and presence of p-waves to support diagnosis of<unk>
Sinus tachycardia
Regular
Wide-complex tachycardia
AV Node Independent
Junctional tachycardia
Narrow-complex tachycardia
Atrial tachycardia 
Ventricular tachycardia