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

January 24-31, 1998
Marilleva, Trento, Italy

RT-57

Consistent atrial pacing: can this new algorithm suppress recurrent paroxysmal atrial fibrillation?

Renato Ricci, Paolo Azzolini, Andrea Puglisi, Carlo Pignalberi*, Andrea Spampinato*, Fulvio Bellocci*, Giuseppe Boriani**, Alessandro Capucci***, Sergio Cavaglia°, Maria Teresa Laudadio°, Francesco De Seta°.
Fatebenefratelli Hospital, Rome, *Villa Tiberia Hospital, Rome, **Policlinico S. Orsola, Bologna, ***Civile Hospital, Piacenza, °Medtronic Italia spa, Rome, Italy

Introduction

Atrial and dual chamber pacing in patients with sinus node disease have been associated with a lower incidence of paroxysmal atrial fibrillation (PAF)^1-3. Many different mechanisms have been considered in the prevention of PAF recurrences: reduced frequency of premature atrial contractions with fewer chance to initiate PAF, short-long atrial cycle prevention, reduced dispersion of conduction and refractoriness, reduced intra-atrial pressure and attenuated stretch-triggered arrhythmogenesis, maintenance of high degree of exit block from all natural subsidiary atrial pacemakers^4,5.

There are a variety of approaches to the prevention of atrial fibrillation with pacing^6,7. A consistent atrial pacing (CAP) algorithm has been designed to achieve a high percentage of atrial pacing (AP) as a means to suppress PAF. This software can be placed in the pacemaker via telemetry using a custom research telemetry device.

The telemetry device attaches to a standard IBM class personal computer. Transmission of the software into the pacemaker takes less than 3 minutes. Follow-ups to retrieve diagnostic data take just several minutes. The software includes a diagnostic which can be interpreted by a special Microsoft Excel spreadsheet.

CAP algorithm

CAP algorithm monitors beat by beat spontaneous atrial activity and continuously updates the atrial escape interval (AEI) to overdrive suppress it. After every sensed atrial event AEI is shortened by a programmable value (delta deceleration). After a programmable number of paced atrial events (plateau beats) AEI is lenghtened by a programmable value (ARS delta). AEI shortening is limited by the programmed upper rate value. AEI lenghtening is limited by the programmed lower rate value. In figure 1 CAP intervention on sinus rhythm is shown: after two sinus beats AEI interval is shortened by 100 msec from 930 to 830 (the eighth atrial cycle). In figure 2 CAP intervention after a short run of premature atrial complexes is represented: AEI interval is shortened from 1000 to 750 msec. In figure 3 CAP intervention on atrial tachycardia is considered: AEI is shortened to the programmed upper rate value (500 msec).