DANPACE, a Danish multicentre randomized trial comparing single lead atrial and dual chamber pacing in patients with sick sinus syndrome, concludes that dual chamber pacing, which was associated with lower rates of atrial fibrillation and re-operation, "should be the preferred pacing mode". The study was presented as part of a Hotline session at European Society of Cardiology Congress 2010.

Behind the conclusion lies a 20-site study of 1415 subjects with sick sinus syndrome referred for their first pacemaker implantation. Pacemakers are routinely used to treat patients suffering from sick sinus syndrome.

The patients were randomized equally to single-lead atrial or dual-chamber pacemakers and their progress followed for a mean of 6.4 years, producing over 7000 operational years of evidence. Results showed that all-cause mortality rates were similar in both groups, 29.6% in the single-lead atrial pacemaker group and 27.3% in the dual chamber group. However, the prevalence of paroxysmal atrial fibrillation was lower in the dual chamber group than in the single-lead group (HR 0.79, p=0.024), with significantly fewer dual chamber patients requiring pacemaker re-operation during follow-up (HR 0.50, p<0.001).

Summarizing the outcome, principal investigator Dr. Jens Cosedis Nielsen from the Department of Cardiology, Skejby Hospital in Aarhus, Denmark, said: "The results showed that, when compared with dual-chamber pacing, single-lead atrial pacing was associated with a 27% increase in the risk of developing atrial fibrillation and a doubling of the risk of having to undergo a pacemaker re-operation.

"In prior trials, ventricular stimulation has been found to increase the incidences of atrial fibrillation and heart failure. However, in this patient group we demonstrated for the first time that dual-chamber pacing actually decreases atrial fibrillation and has no influence on the incidence of heart failure when compared with single-lead atrial pacing without ventricular stimulation."