Prehospital management of supraventricular tachycardia in Victoria, Australia: epidemiology and effectiveness of therapies.

Objective: The present study examined patient demographics, characteristics and the effectiveness of current prehospital supraventricular tachycardia (SVT) management by ambulance paramedics in Victoria, Australia.

Method: We conducted a retrospective study of all Victorian patients attended by paramedics between 14 February 2012 and 13 February 2013, where SVT was the initial or final diagnosis. Patients were excluded if SVT was not captured on ECG, incomplete data were recorded, or SVT began after initial assessment. Data were extracted from the VACIS(®) clinical data warehouse. Accuracy of paramedic SVT diagnosis was examined.

Results: Nine hundred and thirty-three patients were enrolled, including 882 (94.5%) adults and 564 (60.5%) women. Mean adult and paediatric (<18 years) patient ages were 57.5 (SD 18.1) and 10.0 (SD 4.5) years, respectively. Median ambulance response time was 11.0 (IQR 8.0) min. Paramedics correctly identified SVT in 119/123 (96.7%, 95% CI: 91.5, 99.0) of adult ECG strips examined. There were 273/882 (31.0%) patients who spontaneously reverted while in paramedic care. Valsalva manoeuvre was undertaken by 212/882 (24.0%) patients and reverted the SVT in 99/358 (27.7%) attempts. Verapamil was administered to 38/882 (4.3%) patients and reverted 33 (86.8%). Aramine was administered to 43/882 (4.9%) patients and 35 reverted following administration (81.4%). Synchronised cardioversion (70 J) reverted four patients at first attempt. Ultimately, 438 (49.7%) patients remained in SVT on arrival at hospital.

Conclusion: Patient characteristics associated with SVT are more likely to be middle-aged women with a history of hypertension and hypercholesterolaemia. Therapies were underutilised leading to reduced clinical guideline effectiveness. Where therapies were instigated, reversion rates are greater than previously reported.