ADENOSINE FOR THE PREHOSPITAL TREATMENT OF PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA

Study objective: To determine the efficacy and feasibility of adenosin e for the treatment of paroxysmal supraventricular tachycardia (PSVT) in the prehospital setting. Design: Prospective case series. Setting: Large, urban, advanced life support emergency medical services system. Participants: One hundred twenty-nine adult patients with PSVT, as id entified by paramedic personnel. Pregnant patients and those taking ca rbamazepine or dipyridamole were excluded. Interventions: Dose of 12 m g adenosine by rapid IV push followed by a 5-mL saline flush and a rep eat dose of 12 mg adenosine IV push if the patient's rhythm remained u nchanged. Measurements and main results: Six-second lead II rhythm str ips and vital signs were documented before and 2 minutes after the adm inistration of adenosine. Demographic information, past medical histor y, medications, number of adenosine doses given, and complications wer e recorded by the paramedic on a case-report form. One hundred six of 129 (82%) of the case-report forms included the rhythm strips from bef ore and after adenosine administration. Actual initial rhythms were de termined by a consensus panel. The initial rhythms were PSVT in 79% (8 4 of 106) of patients, atrial fibrillation in 12% (13 of 106), sinus t achycardia in 5% (five of 106), atrial flutter in 2% (two of 106), and ventricular tachycardia in 2% (two of 106). Eighty-five percent (71 o f 84) of patients in PSVT were successfully converted to sinus rhythms ; four (5.6%) of these patients required a second 12-mg dose. One pati ent in atrial fibrillation spontaneously converted to normal sinus rhy thm and one patient in ventricular tachycardia converted after adenosi ne. All other patients not initially in PSVT remained in their initial rhythm. Complications occurred in 12 of 129 patients and included che st pain (five), flushing (three), shortness of breath (two), nausea (o ne), anxiety (one), dizziness (one), headache (one), and seizure (one) . All complications were transient and required no treatment. Prior hi story of PSVT was the only variable associated with a higher rate of c onversion (P=.029). Conclusion: Paramedics are able to accurately iden tify PSVT using a single lead. Adenosine is safe and effective treatme nt for PSVT in the prehospital setting. This series is the largest pre hospital study of adenosine use to date.