Comparison of clinical characteristics between malignant and non-malignant vasovagal syncope based on propensity score matching

Background Vasovagal syncope (VVS) is a significant cause of syncope. However, a subset of VVS patients, defined as having malignant VVS, experience prolonged cardiac arrest during episodes (defined as > 3s), with a preference for the implantation of pacemakers. Research on malignant VVS remains limited, and its risk factors have not been fully clarified. This study aimed to identify the clinical characteristics and risk factors associated with malignant VVS. Methods Patients with ECG-confirmed cardiac arrest(> 3s) during syncope were assigned to the malignant VVS group during HUT. After Propensity Score Matching (PSM), given the small sample size of patients with malignant VVS, statistical analyses included univariate comparisons, multivariate logistic regression, receiver operating characteristic (ROC) curve analysis, and decision curve analysis (DCA). Results Patients comprised 26 in the malignant VVS group and 21 matched in the control group. The malignant VVS group had a significantly higher incidence of central triggers and a higher baseline diastolic blood pressure. Multivariate logistic regression identified central triggers and elevated DBP as independent risk factors for malignant VVS. The ROC curve showed that the combined model of DBP and central triggers had the best diagnostic efficacy. DCA confirmed this combined model maintained a stable, high net benefit across all threshold probability ranges. Conclusions Elevated baseline DBP and the presence of central triggers are core screening indicators for malignant VVS. The diagnostic model combining two factors exhibits excellent discriminatory ability and clinical utility, providing a reliable tool for the early identification and individualized management of patients with malignant VVS.