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Ventricular Rate Stabilization in patients with permanent atrial fibrillation and single-chamber ventricular pacemaker. The RARE-PEARL Study


Background. In patients with permanent atrial fibrillation (AF) rate irregularity can cause symptoms and impair the pumping function of the heart. Ventricular pacing at a rate close to the mean spontaneous ventricular rate can result in a more stable ventricular rate. Specific algorithms for automatic Ventricular Rate Stabilization (VRS) were designed and implemented in commercially available pacemakers. To assess this dynamic rate control we designed the RARE-PEARL study: prospective, randomized, cross-over, double-blinded.

Methods. Patients with permanent AF, symptomatic episodes of brady-tachycardia, left ventricular ejection fraction (LVEF) >40%, NYHA class I/II, were eligible for enrolment. Each patient (n = 67) was implanted with a single-chamber VVIR pacemaker (models C20 or T20, Vitatron BV, The Netherlands) equipped with the VRS algorithm. At the end of  a four week of stabilization period, patients were randomized to VRS algorithm ON or OFF (2 months) and then crossed-over for the second phase (2 months). Primary endpoint was patient’s preference.

Results. Sixty six patients ended the study: 19 (29%) had no preference; 15 (23%) preferred the phase with the algorithm OFF, 32 (48%) algorithm ON (p<0.0001, algorithm ON vs OFF). In 58% of patients the algorithm ON caused an increase of ventricular pacing percentage > 10%. The ventricular pacing percentage was 82±10% with algorithm ON vs 59±26% with algorithm OFF (p<0.0001). Symptoms did not differ significantly.

Conclusions. The VRS algorithm significantly increases the ventricular pacing percentage in patients with permanent AF. This pacing function is preferred by the majority of patients implanted with a single-chamber VVIR pacemaker.

Credits: Eraldo Occhetta; Gianfranco Mazzocca; Carla Svetlich; Pietro Scipione; Alessandro Fabiani; Massimo Giammaria; Serafino Orazi; Giorgio Corbucci



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