American College of Cardiology

American College of Cardiology

March 20, 2017
3 min read

Closed-loop stimulation pacing program reduces syncope in SPAIN trial

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WASHINGTON — A pacemaker delivering a closed-loop stimulation pacing program was associated with a sevenfold reduction in syncope, researchers reported at the American College of Cardiology Scientific Session.

For the SPAIN study, Gonzalo Baron-Esquivias, MD, PhD, FESC, associate professor, chief of the clinical cardiology section and head of studies in the cardiology department at Virgien del Rocio University Hospital, Seville, Spain, and colleagues enrolled 54 patients aged 40 years and older with recurrent reflex vasovagal syncope (mean past syncopal episodes, 12; interquartile range, 9-20). Patients were randomly assigned to receive the closed-loop stimulation program (DDD-CLS, Biotronik) designed to respond to contractions preceding syncope or a control pacing program (DDI) that is not designed for such responses.

Group A received DDD-CLS pacing mode followed by DDI pacing mode. Group B received DDI pacing mode followed by DDD-CLS pacing mode. Each mode lasted for 12 months or, in the DDI group, until there were three episodes of syncope in 1 month, at which point they were crossed over to DDD-CLS.

Gonzalo Baron-Esquivias

“In a [previous long-term] study, we showed there is no benefit of [conventional] pacing” in patients with recurrent reflex vasovagal syncope, Baron-Esquivias said during a presentation. “Today, we all think pacing is not the answer for those patients. But there is a new mode called CLS that detects the changes before a vasovagal episode in the heart of those patients. The pacemaker then begins to stimulate to avoid the syncopal episodes.”

The primary efficacy outcome was reduction by at least 50% the overall number of syncope episodes compared with DDI. Other outcomes of interest included time to first recurrence of syncope in Group A vs. Group B and in DDD-CLS mode vs. DDI mode.

Forty-six patients (mean age, 56 years; 48% men) were available for the primary analysis.

In Group A, the proportion of patients with at least a 50% reduction in the number of syncopal episodes was 72.22% in DDD-CLS mode (95% CI, 46.52-90.31), while in Group B, the proportion of patients with at least a 50% reduction in the number of syncopal episodes was 100% in DDD-CLS mode (95% CI, 39.76-100; Mailand-Gard Test P = .0172; Prescott analysis P = .0003), according to the researchers.

Only 8.7% of patients had syncope in DDD-CLS mode, vs. 45.65% in DDI mode (absolute risk reduction, 37%; number needed to treat = 2.7), Baron-Esquivias said.


Time to first syncope was faster in DDI mode than in DDD-CLS mode (OR = 0.1133; 95% CI, 0.349-0.3684). In a time-to-event Cox proportional hazards model, the HR for syncope in DDI mode was 6.7281 (95% CI, 2.2905-19.763), he said.

“DDD-CLS pacing, compared to DDI sham pacing in patients older than 40 years old with cardioinhibitory refractory neurally reflex vasovagal syncope ... has a sevenfold reduction in the recurrence of syncope and significantly prolonged time to first syncope recurrence,” Baron-Esquivias said during the presentation. by Erik Swain


Baron-Esquivias G, et al. Late-Breaking Clinical Trials. Presented at: American College of Cardiology Scientific Session; March 17-19, 2017; Washington, D.C.

Disclosure: The study was funded by the Investigation Agency of the Spanish Society of Cardiology, which received an unrestricted grant from Biotronik Spain. Baron-Esquivias reports no relevant financial disclosures.