The Syncope-Stopper Study (ANZCTR Registration: ACTRN12622001553763) is an Australian randomized controlled trial evaluating the safety, efficacy, and cost-effectiveness of early pacemaker implantation compared to standard care for high-risk patients presenting with unexplained syncope.
Study Design & Objective
The central hypothesis is that an upfront permanent pacemaker (the “Syncope-Stopper”) is the safest and most optimal management strategy for a specific subset of high-risk patients, eliminating the need for prolonged diagnostic monitoring.
- Design: Open-label, parallel-group, randomized controlled trial.
- Target Enrollment: Approximately 180 participants (90 per group). Final results show 200 participants
- Lead Institution: Monash University.
Participant Population
- Adults hospitalized with unexplained syncope.
- Patients must exhibit additional high-risk features for recurrent syncope. The study utilizes a novel DROP score to help identify the patients at the highest risk of bradycardia.
Treatment Arms
Participants were randomized 1:1 into two groups:
- Intervention (Upfront Pacing): Patients undergo immediate implantation of a permanent pacemaker by a cardiac electrophysiologist or cardiologist.
- Control (Standard Care): Patients receive conventional management as dictated by their treating medical team. At the clinician’s discretion, this may include no further investigations, Holter monitoring, or the insertion of an implantable loop recorder (ILR).
According to a summary posted on X, device type, manufacturer and programming was left to the discretion of the implanter. Loop recorder was designated as the primary monitoring modality.
Primary Endpoints
Participants are followed through face-to-face visits for 12 months. The study measures a composite primary endpoint assessing the frequency of:
- Cardiovascular death
- Recurrent syncope
- Bradycardia resulting in delayed pacemaker implantation
- Device-related complications
ESC 2026 Presentation Details
The final results of the Syncope-Stopper trial were recently presented as a late-breaking clinical trial at the European Society of Cardiology (ESC) Congress in Munich.
- Session: Hot Line 10: Progress in syncope and CRT
- Date: Monday, August 31, 2026
- Presenter: Jeremy William (The Alfred Hospital, Melbourne, Australia)
Key Clinical Results
The trial evaluated whether upfront permanent pacing improves outcomes for high-risk patients (aged 55+ with at least one unexplained syncopal episode in the prior year and a DROP score ≥2) without documented bradycardia.
- Primary Endpoint: A composite of recurrent syncope, bradycardia requiring a pacemaker, cardiovascular death, and device-related complications at 12 months.
- Findings: Upfront pacing significantly reduced the primary endpoint compared to standard care (17.2% vs. 31.7%; p=0.014).
- Conclusion: The findings suggest that utilizing the novel DROP score enables targeted, proactive pacing that successfully prevents recurrent syncope and associated morbidity in this high-risk population.
Reference
Because the trial was just presented as a late-breaking Hot Line study at ESC 2026, the primary outcomes data is currently available via the ESC Congress presentations and press materials.
Reference
The DROP score is a 4-point clinical risk tool used to predict which patients with unexplained syncope are at the highest risk for bradyarrhythmias and would most likely benefit from a permanent pacemaker. It was derived by analyzing patients who received implantable loop recorders (ILRs) to identify which baseline clinical and ECG characteristics strongly predicted the eventual need for pacing.
Score Components
The acronym represents four independent predictors, with 1 point assigned for each present factor (maximum score of 4):
| Letter | Clinical Predictor | Definition |
| D | Distal conduction disease | Presence of bundle branch block or fascicular block on baseline ECG |
| R | pR interval prolongation | First-degree AV block on baseline ECG |
| O | Older age | Age > 65 years |
| P | Precipitating factors absent | Lack of typical vasovagal triggers (e.g., overheating, posture changes, or exercise) |
Interpretation
- Score 0–1: Low risk. In the derivation study, no patients with a score of 0 progressed to needing a pacemaker over 3 years of follow-up.
- Score ≥2: High risk. A score of 2 or greater strongly predicts the requirement for pacing. This ≥2 threshold is what the recent Syncope-Stopper trial uses as a core inclusion criterion for its upfront pacing intervention arm.
Reference
While the Syncope-Stopper trial protocol was presented at ESC 2026, the DROP score itself was originally developed and published by the same Australian research group in 2022.
Xiao, X., William, J., Kistler, P. M., & Voskoboinik, A. (2022). Prediction of Pacemaker Requirement in Patients With Unexplained Syncope: The DROP Score. Heart, Lung and Circulation, 31(7), 999-1005.