Initial 12 mg Versus 6 mg Adenosine for Supraventricular Tachycardia in the Emergency Department.

Abstract

Objectives: This study aimed to compare the efficacy and safety of an initial 12 mg versus 6 mg adenosine dose for sinus rhythm conversion in patients presenting with supraventricular tachycardia (SVT) in the emergency department (ED).

Methods: This prospective observational study was conducted between February 2025 and January 2026. Adult patients (≥ 18 years) presenting to the ED with hemodynamically stable SVT confirmed by 12-lead electrocardiography (ECG) were included. Patients were categorized into two groups according to the initial adenosine dose administered (6 mg vs. 12 mg). To address potential selection bias, 1:1 propensity score matching (PSM) was performed. The primary outcome was successful first-dose sinus rhythm conversion. Secondary outcomes included adenosine-related adverse effects and SVT recurrence during the ED stay.

Results: A total of 142 patients were analyzed (n = 71 per group). First-dose conversion was significantly higher with 12 mg compared with 6 mg (83.1% vs. 52.1%). In the PSM cohort (n = 104), the 12 mg dose maintained its superior efficacy (82.7% vs. 53.8%). The PSM-adjusted odds ratio for successful conversion was 4.12 (95% confidence interval [CI]: 1.85-9.14), with a number needed to treat (NNT) of 3.8 (95% CI: 2.5-8.3). SVT recurrence was numerically lower in the 12 mg group (1.4% vs. 9.9%). Adverse effects were similar between groups.

Conclusions: An initial 12 mg adenosine dose was associated with higher first-dose sinus rhythm conversion than 6 mg, while adverse effects were similar between groups.