Minimizing atrial pacing did not prevent atrial fibrillation (AFib) in patients with sinus node dysfunction, according to findings from the DANPACE II trial presented at ESC Congress 2023.

Researchers from Denmark randomized 539 patients with sinus node dysfunction and an indication for a first-time dual chamber (DDD) pacemaker into two groups: 1) base rate of 60 beats per minute (bpm) and rate-adaptive DDD (DDDR-60 group); or 2) base rate of 40 bpm and non-rate-adaptive DDD (DDD-40 group). All patients were followed for two years by remote monitoring and ambulatory visits were scheduled after three, 12 and 24 months.

After two years, the primary endpoint assessing the number of AFib episodes detected by pacemaker and lasting more than six minutes was similar across both groups at 46% each. Secondary endpoints, including episodes of AFib with a duration longer than six hours or 24 hours, progression to permanent or persistent AFib, cardioversions for AFib, and all-cause mortality, occurred at similar rates in both treatment groups during two years of follow up. Additionally, quality of life and performance on the 6-minute hall-walk test after 12 months were similar between the two groups.

In other findings, significantly more patients in the DDD-40 group experienced syncope or presyncope (22%) compared with the DDDR-60 group (13%). Researchers also noted that the crossover rate was significantly higher for patients randomized to DDD-40 compared to DDDR-60. Among the 62 (23%) patients who crossed from DDD-40 to DDDR-60, the indication was syncope or presyncope in 18 (29%) patients, chronotropic incompetence in 38 (61%) patients, and not specified in five (8%) patients, they said. Only 3% of patients in the DDDR-60 group had their device reprogrammed to a lower base rate.

"Minimizing atrial pacing in patients with sinus node dysfunction does not reduce the incidence of AFib," said Mads Brix Kronborg, MD, of Aarhus University Hospital in Denmark. "Programming a base rate of 40 bpm without rate-adaptive pacing increases the risk of syncope or presyncope."

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, EP Basic Science, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: ESC Congress, ESC23, ACC International, Atrial Fibrillation, Sick Sinus Syndrome, Pacemaker, Artificial, Syncope

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