To confirm the efficacy of pre-hospital administration of adenosine, using a 6 milligram (mg) initial dosing regimen, for the treatment of paroxysmal supraventricular tachycardia (PSVT).

Urban, suburban, rural emergency medical services (EMS) system in Clark County, Washington with advanced life support (ALS) patient transports. Concurrent, paramedic Medical Incident Report (MIR) review was conducted for 102 patients receiving prehospital adenosine during a 42-month period. Patients were administered 6 mg of adenosine using an intravenous (IV) bolus followed by 10 ml of balanced salt solution flush. If the patient's rhythm remained unchanged, the dosing regimen was increased to 12 mg followed by a 10 ml flush. This was repeated once more if the rhythm remained unchanged, to a total maximum dose of 30 mg. Medical direction for administration of adenosine was in the form of standing orders rather than direct (on-line) medical control.

Seventy-four of 102 patients had PSVT as determined by physician analysis of the initial six-second electrocardiographic rhythm strip (ECG) recording. Sixty-six of these patients converted their cardiac rhythm from PSVT using adenosine; 46 (70%) converted with the initial 6 mg bolus. Fifteen patients converted after receiving the second dose (12 mg); and five patients required 30 mg.

These results show that for paramedics, adenosine is an effective treatment for PSVT. An initial bolus of 6 mg converts the majority of cases. Eighty-nine percent of cases of confirmed PSVT converted with adenosine administration.