Syncope in paced patients with sick sinus syndrome from the DANPACE trial: incidence, predictors and prognostic implication

Objectives Syncope is a cause of significant morbidity in sick sinus syndrome (SSS) which may not be resolved with permanent pacemaker therapy. We aimed to determine the incidence, predictors and prognostic implication of syncope in paced patients with SSS. Methods We studied 1415 patients (mean age 72.9 years, SD 11.1) with SSS who were randomised in the DANPACE study to either rate-responsive single chamber pacing (n=707) or rate-responsive dual chamber pacing (n=708). Main outcome measures were patient-reported syncope after pacemaker implantation and mortality. Results Mean follow-up was 5.4 years (SD 2.6). A total of 247 (17.5%) patients experienced syncope after pacemaker implantation (135 (19%) from the rate-responsive single chamber pacing group, and 112 (15.8%) from the rate-responsive dual chamber pacing group. Predictors of syncope post pacemaker implantation included: age 0–39 years (HR 2.9, 95% CI 1.4 to 6.3, p=0.01; reference range 60–79 years), age ≥80 years (HR 1.4, 95% CI 1.0 to 1.8, p=0.03), syncope prior to pacemaker implant (HR 1.8, 95% CI 1.4 to 2.3, p