Intravenous adenosine in the prehospital treatment of paroxysmal supraventricular tachycardia

Abstract

Study objective: To determine the clinical efficacy and safety of IV adenosine administration in the field for the treatment of paroxysmal supraventricular tachycardia (PSVT). Design: Prospective, consecutive case series. Setting: An urban emergency medical services system. Participants: Thirty-seven adult patients in whom paramedics made the diagnosis of PSVT. Interventions: Six milligrams of adenosine was administered by rapid IV bolus. If there was no effect within two minutes, a 12-mg bolus was given. This dose was repeated once if necessary. If there still was no effect, the medical command physician was contacted for further management. Measurements: Vital signs, symptoms, and a single-channel ECG were recorded before, during, and after the administration of adenosine. Results: On review of the ECG tracings, 26 patients (70%) were in PSVT. Eleven had rhythms other than PSVT on review, including five with atrial fibrillation, four with sinus tachycardia, and two with ventricular tachycardia. Of the 26 patients with PSVT, 23 (88%) converted to sinus rhythm after adenosine administration. Eleven patients were hypotensive at presentation. Seven of these were in PSVT and became hemodynamically stable on conversion with adenosine. The four hypotensive patients with rhythms other than PSVT (two with atrial fibrillation and two with ventricular tachycardia) had no change in blood pressure after adenosine administration. Nine patients were subsequently found to have wide-complex tachycardia. None of these patients suffered hemodynamic compromise after adenosine administration, and side effects were infrequent, mild, and transient. Conclusion: Adenosine appears to be effective and safe for the prehospital treatment of PSVT.