Weight-adjusted adenosine and first-dose conversion success in supraventricular tachycardia: a prospective cohort study

Background Current guidelines recommend a standard fixed initial dose of 6 mg adenosine for supraventricular tachycardia (SVT). However, rising obesity rates may reduce the efficacy of this fixed-dose strategy. We aimed to evaluate the impact of body weight on first-dose adenosine success and to identify an optimal weight-adjusted dose. Methods This prospective observational study included 155 adult SVT patients refractory to vagal maneuvers at a tertiary emergency department (ED). All patients received an initial 6 mg dose of IV adenosine. Success was defined as conversion to sinus rhythm (SR). Weight-adjusted doses (mg/kg) were compared between success and failure groups, and ROC analysis was performed to identify optimal cutoffs. Results The first-dose conversion rate was 58.1%. Patients with successful conversion had significantly lower body weight (74.0 ± 14.3 kg vs. 81.9 ± 16.2 kg, p = 0.001). The weight-adjusted dose was significantly higher in the success group compared to the failure group (0.082 vs. 0.074 mg/kg, p < 0.001). ROC analysis revealed that a weight-adjusted dose ≥ 0.076 mg/kg predicted conversion with 67.8% sensitivity and 60.0% specificity. Specificity increased to 90.8% at a cutoff of ≥ 0.10 mg/kg. Conclusion Our findings suggest that the standard fixed 6 mg initial dose of adenosine may be insufficient for contemporary populations with higher body weight. A weight-adjusted initial dose, particularly targeting 0.09-0.1 mg/kg, may optimize first-dose conversion to sinus rhythm in patients with SVT.