Left atrial reverse remodeling and prevention of progression of atrial fibrillation with atrial resynchronization device therapy utilizing dual-site right atrial pacing in patients with atrial fibrillation refractory to antiarrhythmic drugs or catheter ablation.

INTRODUCTION: Dual-site right atrial pacing (DAP) produces electrical atrial resynchronization but its long-term effect on the atrial mechanical function in patients with refractory atrial fibrillation (AF) has not been studied.

METHODS: Drug-refractory paroxysmal (PAF) and persistent AF (PRAF) patients previously implanted with a dual-site right atrial pacemaker (DAP) with minimal ventricular pacing modes (AAIR or DDDR mode with long AV delay) were studied. Echocardiographic structural (left atrial diameter [LAD] and left ventricular [LV] end diastolic diameter [EDD], end systolic diameter [ESD]) and functional (ejection fraction [EF]) parameters were serially assessed prior to, after medium-term (n = 39) and long-term (n = 34) exposure to DAP.

RESULTS: During medium-term follow-up (n = 4.5 months), there was improvement in left atrial function. Mean peak A wave flow velocity increased with DAP as compared to baseline (75 ± 19 vs. 63 ± 23 cm/s, p = 0.003). The long-term impact of DAP was studied with baseline findings being compared with last follow-up data with a mean interval of 37 ± 25 (range 7-145) months. Mean LAD declined from 45 ± 5 mm at baseline to 42 ± 7 mm (p = 0.003). Mean LVEF was unchanged from 52 ± 9 % at baseline and 54 ± 6 % at last follow-up (p = 0.3). There was no significant change in LV dimensions with mean LVEDD being 51 ± 6 mm at baseline and 53 ± 5 mm at last follow-up (p = 0.3). Mean LVESD also remained unchanged from 35 ± 6 mm at baseline to 33 ± 6 mm at last follow-up (p = 0.47). During long-term follow-up, 30 patients (89 %) remained in sinus or atrial paced rhythm as assessed by device diagnostics at 3 years.

CONCLUSIONS: DAP can achieve long-term atrial reverse remodeling and preserve LV systolic function. DAP when added to antiarrhythmic drug (AAD) and/or catheter ablation (ABL) maintains long-term rhythm control and prevents AF progression in elderly refractory AF patients. Reverse remodeling with DAP may contribute to long-term rhythm control.