Risk of syncopal recurrences in patients treated with permanent pacing for bradyarrhythmic syncope: role of correlation between symptoms and electrocardiogram findings

Aims: To evaluate the risk of syncopal recurrences after pacemaker implantation in a population of patients with syncope of suspected bradyarrhythmic aetiology.

Methods and results: Prospective, multicentre, observational registry enrolling 1364 consecutive patients undergoing pacemaker implantation for syncope of bradyarrhythmic aetiology (proven or presumed). Before pacemaker implantation, all patients underwent a cardiac work-up in order to establish the bradyarrhythmic aetiology of syncope. According to the results of the diagnostic work-up, patients were divided into three groups: Group A, patients in whom a syncope-electrocardiogram (ECG) correlation was established (n = 329, 24.1%); Group B, those in whom clinically significant bradyarrhythmias were detected without a documented syncope-ECG correlation (n = 877, 64.3%); and Group C, those in whom bradyarrhythmias were not detected and the bradyarrhythmic origin of syncope remained presumptive (n = 158, 11.6%). During a median follow-up of 50 months, 213 patients (15.6%) reported at least one syncopal recurrence. Patients in Groups B and C showed a significantly higher risk of syncopal recurrences than those in Group A [hazard ratios (HRs): 1.60 and 2.66, respectively, P < 0.05]. Failure to establish a syncope-ECG correlation during diagnostic work-up before pacemaker implantation was an independent predictor of syncopal recurrence on multivariate analysis (HR: 1.90; P = 0.002).

Conclusion: In selecting patients with syncope of suspected bradyarrhythmic aetiology for pacemaker implantation, establishing a correlation between syncope and bradyarrhythmias maximizes the efficacy of pacing and reduces the risk of syncopal recurrences.