Patients with syncope who received a pacemaker that delivers a pacing program designed to detect and stop the arrhythmia that precede syncope had a seven-fold reduction in fainting compared with patients in a placebo pacing group, according to the SPAIN trial results presented March 19 at ACC.17 in Washington, DC.

The study, led by Gonzalo Baron-Esquivias, MD, PhD, et al., is the first prospective double-blind placebo-controlled trial to show robustly positive results for the Closed Loop Stimulation (DDD-CLS) pacing program in patients with recurrent syncope. In the SPAIN trial, Baron-Esquivias and his colleagues recruited 54 patients aged 40 or older from 12 medical centers in Spain and Canada. All had experienced more than five episodes of syncope in their lifetimes, with more than two in the previous year. The researchers randomly assigned half to receive DDD-CLS pacing for 12 months and the other half to the control DDI pacing program. After 12 months, patients were crossed over to the other pacing program. If a patient in either group had more than three episodes of syncope in one month, their pacing assignment was switched.

The primary endpoint of a significant reduction in syncope with DDD-CLS compared with control pacing was met. During the trial, four patients experienced syncope while receiving DDD-CLS pacing, compared with 21 patients who fainted during DDI pacing, a statistically significant difference. Among patients initially assigned to DDD-CLS, 72.2 percent had a reduction of more than 50 percent in syncope episodes within the first year, but syncope recurred after they crossed over to the DDI group. Patients who crossed over to DDD-CLS after a year of placebo pacing saw a reduction of more than 50 percent in syncope episodes during the second year.

Baron-Esquivias, who currently uses DDD-CLS pacing to treat patients with recurrent syncope in his own practice, said that if these findings are confirmed by larger, ongoing studies, such as the ongoing BioSync CLS trial, he expects that international guidelines will be changed to recommend DDD-CLS pacing in these patients.

Keywords: ACC17, ACC Annual Scientific Session, Arrhythmias, Cardiac, Algorithms, Bradycardia, Carotid Sinus, Dichlorodiphenyldichloroethane, Electrocardiography, Heart Arrest, Odds Ratio, Recurrence, Syncope, Syncope, Vasovagal

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