Risk of death and thrombosis in patients admitted to the emergency department with supraventricular tachycardias

Background: Few data are available on the clinical course of patients with supraventricular tachycardia (SVT). Objective: To assess the one-year risk of adverse events in patients with SVT. Methods: Retrospective study with TriNetX. Based on the ICD-10-CM codes recorded at the emergency department admission, patients not on oral anticoagulant were categorized as SVT, atrial fibrillation (AF), atrial flutter, or control group (CTRL). Primary outcome was the one-year risk of a composite of all-cause death and thromboembolism. Cox-regression analysis was used to produce hazard ratios(HRs) and 95% confidence intervals (CI) after 1:1 propensity score matching (PSM). Sensitivity analyses were performed in clinically relevant subgroups. Incident AF and new OAC prescriptions were reported over the study period. Results: We identified 23,524 SVT patients (54.6±19.3 years, 59.5% females), 5,413 atrial flutter patients (66.9±15.7 years, 35.2% females), 157,715 AF patients (72.5±14.0 years, 43.6% females), and 150,807 CTRL (43.0±17.4 years, 58.7% females). After PSM, the risk of composite outcome in SVT patients was higher compared to CTRL (HR 2.89, 95%CI 2.65-3.17), but lower compared to atrial flutter patients (HR 0.87, 95%CI 0.79-0.97) and AF patients (HR 0.69, 95%CI 0.65-0.73). The risk of adverse events in SVT patients was more pronounced during the first 30 days, amongst males, aged ≥65 years, or with multimorbidity. SVT patients had an increased risk of incident AF compared to CTRL. Conclusions: The heightened risk of adverse events in SVT patients appears to be most pronounced in the short term, and partly associated with the increased likelihood of incident AF.