DANPACE: All-cause mortality in patients with sick sinus syndrome did not differ with AAIR, DDDR pacing

Nielsen J. Session 708001–708002.

Issue: November 2010

European Society of Cardiology Congress 2010

Data from a new study has suggested no significant difference in all-cause mortality for the use of single-lead atrial pacing or dual-chamber pacing in patients with sick sinus syndrome. However, the rate of paroxysmal atrial fibrillation and re-operation was significantly higher in the single-lead atrial pacing group.

The DANPACE trial was a Danish multicenter study consisting of 1,415 patients (73.0 ± 11.3 years, 64.5% women) with sick sinus syndrome who were randomly allocated to either rate adaptive single-lead atrial (AAIR; n=707) pacing or rate adaptive dual-chamber (DDDR, n=708) pacing. Patients were followed for a mean of 5.4 ± 2.6 years.

According to study researchers, all-cause mortality was 29.6% in the AAIR group and 27.3% in the DDDR group (for DDDR, HR=0.94; 95% CI, 0.77-1.14). The incidence of paroxysmal AF was lower in the DDDR group than in the AAIR group (HR=0.79; 95% CI, 0.64-0.97), even after correction for relevant baseline variables. Incidence of chronic AF, stroke and HF did not differ between groups; however, there was a significantly less rate of patients in the DDDR group who underwent re-operation during follow-up than the AAIR group (HR=0.50; 95% CI, 0.39-0.66).

This led the researchers to conclude that DDDR pacing should be the preferred pacing mode in patients with sick sinus syndrome to reduce AF and re-operations.

However, in the presentation’s discussant, Carina Blomström-Lundqvist, MD, with the department of cardiology at Uppsala University Hospital, Uppsala, Sweden, said she was not as convinced by the results.

“In the DANPACE study, the percent of atrial pacing was similar in the AAIR group (58 ± 29%) and the DDDR group (59 ± 31%, P=.52), but the percentage of ventricular beats that were paced in the DDDR group was only 65 ± 33%, which is lower than in the SAVE-PACE trial (99%) and thus may partly explain the lack of deleterious effects usually observed with ventricular pacing regarding occurrence of AF and increased mortality,” she said.

“The study further demonstrated that the vast majority (83%) of sick sinus syndrome patients with AAIR devices remained as randomized, at last follow-up,” Blomström-Lundqvist said. “Further studies with long-term outcomes and economic evaluation of the most optimal pacing modes are therefore needed to identify the preferred pacing device for patients with sick sinus syndrome without evident need for ventricular pacing.”

Follow CardiologyToday.com on Twitter.