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

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

RT-39

Effect of intermittent or continuous overdrive atrial pacing in paroxysmal atrial fibrillation related to brady-tachy syndrome

Giovanni Luca Botto*, R. Ricci*, W. Bonini, T. Broffoni, M. Santini*, A. Puglisi**, P. Azzolini**, C. Pignalberi**, A. Capucci***, G. Boriani****, A.Spampinato°, F. Bellocci°, A. Proclemer°°, A. Grammatico°°°, F. De Seta°°° and the ISSAF/CAP Group.
Sant’Anna Hospital, Como; *San Filippo Neri Hospital, Roma; ***Fatebenefratelli Hospital, Roma; ***Civile Hospital, Piacenza; ****Sant’Orsola Hospital, University of Bologna; °Villa Tiberia Hospital, Roma; °°S. Maria della Misericordia Hospital, Udine; °°° Medtronic Italia, Italy

Abstract

Overdrive Atrial Pacing (OAP) has been associated with a lower rate of recurrent paroxysmal atrial fibrillation (AF). Aim of the study was to evaluate the impact of intermittent or continuous OAP on paroxysmal AF recurrences in a selected population of highly symptomatic brady-tachy patients implanted with a DDDR pacemaker. The study population included 35 patients (mean age 75±9, 16 M, 19 F) affected by brady-tachy syndrome with at least three symptomatic episodes of paroxysmal AF during the last month before implantation. Intermittent OAP was obtained by programming the device in DDDR mode, continuous OAP through a dedicated algorithm, named Consistent Atrial Pacing (CAP), which updates beat by beat the atrial escape interval to overdrive suppress spontaneous atrial activity: both sinus rhythm and premature atrial complexes. Patients were randomized in two groups, DDDR+CAP versus DDDR and followed for two months. After the first month the pacing modality was crossed over. Forty-five % of patients were on antiarrhythmic treatment which did not change during the study period.

Eighty-five % of patients in DDDR and 78% in DDDR+CAP were free from symptomatic PAF recurrences and 41% in DDDR and 28% in DDDR+CAP had no mode switching episodes stored in the pacemaker memory (p=NS).

Both intermittent and continuous OAP strongly decrease PAF recurrences in selected highly symptomatic brady-tachy patients. Continuous OAP significantly increase AP percentage from 78% in DDDR pacing mode alone to 96% in DDDR+CAP (p<0.01) and decrease the number of premature atrial complexes per day from 2.3 in DDDR mode to 0.5 per day in DDDR+CAP pacing mode (p<0.03). A decrease on arrhythmia recurrences may be found in a selected group of patients who experienced very different atrial pacing percentages AP% in CAP OFF (AP%<50%) and CAP ON (AP%>90%) periods.

Key Words