The present study was completed to establish an epidemiological database defining prehospital rapid atrial fibrillation (RAF) and interventions given such patients in the hope of developing recommendations for further treatment protocols. On review of 4,749 paramedic run reports from a low-volume urban emergency medical services (EMS) system, 33 persons (0.69%) presented with RAF. Data collected included vital signs/ventricular rate, patient age, ambulance field times, patient chief complaint, prehospital interventions, efficacy of interventions, additional cardiac rhythms, iatrogenic complications, and patient past medical history. Neither intravenous (IV) diltiazem or electrical cardioversion were used within the 12-month period of this study. Symptomatic/supportive care consisting of observation (72.73%) and interventions (27.27%) with nitroglycerine, furosemide, aspirin, morphine, and/or IV fluid bolus therapy accounted for all prehospital treatment. Paramedics documented improvement in 100% of patients. No cases occurred in which RAF resulted in severe hemodynamic instability. No inappropriate use, point estimate (PE) [(0)/(33) (0.00% to 10.60%)], or unmet need, PE [(0)/(4,716) (0.00% to 0.08%)] of care was noted. The data presented in this study suggest that given similar EMS system characteristics, prehospital RAF is an infrequently encountered, predominantly hemodynamically stable cardiac arrhythmia, readily treatable with symptomatic/supportive care, and cautious observation. The prehospital application of adult advanced cardiac life support guidelines utilizing IV diltiazem and electrical cardioversion for the treatment of RAF may be unnecessary.