13th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 1998

January 24-31, 1998
Marilleva, Trento, Italy

RT-59

Does dual chamber pacing prevent paroxysmal atrial fibrillation in brady-tachy patients?

G. Boriani¹, G.L. Botto², L. Frabetti¹, M. Biffi¹, F. Bellocci³, D. Bernabo⁴, A. Capucci⁵, P. Dini³, G. Leoni⁶, F. Lisi⁷, A. Marchini⁸, P.V. Moracchini⁹, G. Nicotra¹⁰, P. Nigro⁷, A. Puglisi³, R. Ricci³, A. Spampinato³, S. Cavaglia¹¹, F. De Seta¹¹, and the ISSAF Group.
¹Bologna, ²Como, ³Roma, ⁴La Spezia, ⁵Piacenza, ⁶Seriate, ⁷Catania, ⁸Brescia, ⁹Modena, ¹⁰Gorizia, ¹¹Medtronic Italia, Italy

Introduction

Atrial fibrillation (AF) is a common arrhythmia and it is responsible for substantial morbidity. For many patients (pts) natural history of the arrhythmia is progression from the paroxysmal form to the chronic form of the disease¹. It has been demonstrated that paroxysms of AF lead to atrial electrophysiologic changes in humans² and in animals³ that can promote the persistence of the arrhythmia and that make maintenance of sinus rhythm (SR) more difficult.

The role of cardiac pacing in preventing AF in patients at risk for this arrhythmia is a relatively new concept. Many important, but non-randomized retrospective studies, have suggested that pacing in the atrium in pts with sick sinus syndrome (SSS) lead to reduction in the occurence of AF and mortality⁴. It is clear that some of the apparently benefits with DDD pacing are due to the non-randomized allocation of the devices, for this reason some authors emphasized that current retrospective data do not allow a definitive recommendations regarding atrial pacing in pts with SSS but call for a prospective, randomized controlled trial to determine the benefits of atrial pacing⁵. This point is of particular relevance because many of these pts require permanent pacing because of unreliable sinus node function or atrio-ventricular (AV) conduction⁶, thus allowing the opportunity to use novel prophylactic pacing tecniques. Sick sinus syndrome represents an important indication for DDD pacing, and in brady-tachy syndrome (B-T) chronotropic incompetence (CI) is common. In these pts paroxysmal AF (PAF) is frequently bradycardia-mediated and DDDR pacing systems have the potential advantage of providing a reliable chronotropic response in conjunction with maintenance of a relatively normal AV relation and a reduced rate of retrogade atrial stimulation. However, DDDR pacing could theoretically have an arrhythmogenic potential because sensor-driven atrial pacing might occur within the vulnerable period of atrial depolarization, thus inducing PAF.

Therefore we have performed a prospective, controlled, randomized, multicenter study to evaluate the efficacy of DDDR and DDD pacing modes in preventing PAF episodes in pts with B-T syndrome and CI. Here we report the data analysis from the first 42 pts who completed six-month follow-up.