A Clinical Score for Predicting the Paroxysmal Supraven- tricular Tachycardia's Recurrence Risk; a Retrospective Cross-sectional Study

Introduction: Identifying prognostic variables associated with the probability of recurrent paroxysmal supraventricular tachycardia (PSVT) would aid decision-making regarding disposition of the patients. This study aims to develop a clinical scoring system to predict PSVT recurrence after adenosine administration in the emergency department (ED). Methods: This retrospective cross-sectional study was conducted on patients who were referred to the emergency department of Ramathibodi Hospital, a university-affiliated super-tertiary care hospital in Bangkok, Thailand, with diagnosis of PSVT during a 10-year period from 01 January 2010 un-til 31 December 2020. The cases were divided into recurrent and non-recurrent PSVT based on the response to standard treatment and the independent predictors of recurrence were studied using multivariable logistic regression analysis. Results: 264 patients were diagnosed with PSVT and successfully converted by adenosine. 24 (9.1%) had recurrent PSVT, and 240 (90.9%) had no recurrent PSVT in the same ED visit. The risk of PSVT recurrence in ED corresponded with the history of hypertension (p = 0.059), valvular heart disease (p = 0.052), heart rate & GE; 100 (p = 0.012), and systolic blood pressure < 100 after electrocardiogram (ECG) converted to sinus rhythm (p = 0.022) and total dose of adenosine (p = 0.002). We developed a clinical prediction score of PSVT re-currence with an accuracy of 79.5%. A score of 0 (low risk), 1-2 (moderate risk), and > 2 (high risk) had a positive likelihood ratio (LR+) of 0.31, 0.56 and 2.33, respectively. Conclusion: It seems that, using the PSVT recurrence score we could screen the high-risk patients for PSVT recurrence (score > 2) who need to be observed for at least 6-12 hours and receive cardiologist consultation in ED. In addition, the moderate and low-risk group (score 0-2) need to be observed for 1 hour and can be discharged from ED.