Following consent, patients will be randomized to either IV diltiazem (DT) or IV metoprolol (MET). Sealed envelopes containing the randomized treatment protocol will be maintained on the ED premises to be pulled consecutively after a patient has been consented to be in the study. Inside the envelope, the specific treatment plan will be revealed. Treatment with either DT or MET will be initiated using standard CAMC protocol. Deviations from the randomly assigned medication regimen would be at the attending physician's discretion pending vital signs response. If the study drug is stopped or changed to a different type of medication, the patient's participation will continue and medications will be documented with the analysis of results being the intent to treat.