14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-189

Assessment of a new pacing algorithm after atrioventricular junction ablation and DDDR pacemaker implantation for drug-refractory paroxysmal atrial fibrillation

Alessandro Proclemer, Luigi Padeletti*, Carlo Pappone**, Domenico Facchin, Patrizio Mazzone**, Francesco Maggi***, Carlo De Michele***, Tiziana Marotta***.
Istituto di Cardiologia, Fondazione IRCAB, Udine, *Istituto di Cardiologia, Universita di Firenze, **Dipartimentodi Cardiologia, Istituto San Raffaele, Milano, ***Medtronic, Inc., Italy

Radiofrequency ablation of atrio-ventricular junction with dual-chamber rate-responsive pacemaker implantation is an established non-pharmacological approach for ventricular rate control of drug-refractory paroxysmal atrial fibrillation^1-3. The majority of patients, however, continues to suffer recurrent episodes of atrial fibrillation and finally can develop chronic atrial fibrillation. By interrogation of the pacemaker memory function pathological atrial rhythms were in fact reported in 25% out of a 6-month study period, and permanent atrial fibrillation in 24% of cases⁴. To reduce the incidence of both paroxysmal and chronic atrial fibrillation, dual chamber rate responsive pacing has been tested with conflicting results. A recent multicenter study⁵ showed that atrial rate adaptive pacing in the absence of associated symptomatic bradycardia did not prevent early recurrence of paroxysmal atrial fibrillation, nor did it decrease in the short term the frequency or duration of atrial fibrillation recurrences. In that study, however, the atrium was paced only 67% of the time in the group of patients randomized to DDDR mode.

Therapeutic algorithm such as consistent atrial pacing (CAP) has been designed for obtaining a very high value of atrial pacing in the 24h period. Aim of the present prospective randomized study was to test the hypothesis that 1) CAP algorithm reduces the number and duration of recurrent atrial fibrillation episodes, 2) CAP prevents development of chronic AF, 3) CAP improves the main symptoms scale and the quality-of-life (QOL) indexes. Only patients treated by AV junction ablation and DDDR pacemaker implantation for drug-refractory paroxysmal atrial fibrillation in the absence of documented bradycardia were included.