Background <p>Vagal maneuvers are recommended as first-line therapy for hemodynamically stable supraventricular tachycardia (SVT). However, real-world data on their use in prehospital emergency medical services (EMS) remain limited.</p> Aim <p>To evaluate the utilization and effectiveness of the Valsalva maneuver in the prehospital management of tachyarrhythmia, with particular focus on patients with confirmed SVT.</p> Methods <p>A retrospective cohort study was conducted using EMS documentation from a regional EMS system in Poland between 2023 and 2024. Among 93,847 EMS interventions, 235 cases coded as unspecified tachycardia (ICD-10 R00.0) were identified. Data included patient demographics, ECG findings, syncope, performance and outcome of the Valsalva maneuver, and hospital transport decisions. Subgroup analysis focused on patients with ECG-confirmed SVT.</p> Results <p>SVT was documented in 71 patients (30.2%). The Valsalva maneuver was performed in 13 patients (5.5% of the cohort) and in 18.3% of those with confirmed SVT. Sustained conversion to sinus rhythm occurred in 5 of 13 patients (38.5%; 95% CI 13.9–68.4%), with transient improvement in one additional case. All attempts were performed in patients with narrow-complex tachycardia consistent with SVT. Hospital transport occurred in most patients regardless of maneuver performance or outcome.</p> Conclusions <p>In this EMS cohort, the Valsalva maneuver was infrequently used despite guideline recommendations. When performed, rhythm conversion occurred in a minority of cases and did not substantially influence transport decisions. These findings highlight the gap between guideline recommendations and real-world prehospital practice.</p>