The use of atrial overdrive and ventricular rate stabilization pacing algorithms for the prevention and treatment of paroxysmal atrial fibrillation: the Pacemaker Atrial Fibrillation Suppression (PAFS) study

Aims The PAFS study is a randomized, multicentre investigation of the effects of third generation anti-atrial fibrillation pacemaker algorithms in patients with paroxysmal atrial fibrillation (PAF). Methods and results 182 patients (72 ± 9 years, 55% male) with at least three symptomatic episodes of PAF within prior 3 months resistant to two anti-arrhythmics were enrolled. A pacemaker-derived atrial fibrillation (AF) burden of 1-50% was required in the initial induction phase. Seventy-nine patients fulfilled these criteria and were randomized to four, month-long phases in a crossover design. Algorithm phases were 'rate soothing' on, 'ventricular rate stabilization' on, and 'All on', which included these two algorithms plus post-AF response. The algorithm phases were compared to 'All off' dual chamber universal mode (DDD 60) for the analysis. Forty-two percent of patients enrolled in the monitoring phase had no AF. The percentage of AF induced by premature atrial contractions (PACs) was significantly reduced by rate soothing from 25 to 17% (P < 0.05). There was no significant change in AF burden, AF episode number, quality of life, or symptoms with any algorithm (P = ns). Conclusion The rate-soothing algorithm by atrial overdrive pacing reduced PAC-initiated PAF. However, there was no overall change in AF burden, PAF episodes, patient symptoms, or quality of life. Forty-two percent of PAF patients did not show any AF after enrolment, suggesting that bradycardia pacing alone eliminates AF.