Effect Of Omeprazole On Tachycardia-induced Electrical Remodeling Of Rabbit Atria

Backgroud Atrial fibrillation (AF) are known to induce atrial electrical remodeling, including shortening of atrial refractoriness , lose of rate adaptability, and increase of AERP disperation. It is reported that proton pump inhibitor (PPI) therapy of gastroesophageal reflux disease in patients with lone paroxysmal atrial fibrillation (PAF) leads to a reduction of PAF-related symptoms, but the exact machanism is not clear. The aim of this study is to investigate the effects of Omeprazole (PPI) on tachycardia-induced acute atrial electrical remodeling in rabbits.Methods Twenty-four rabbits were divided into 4 groups randomly: normal saline (NS) group, Omeprazole group, NS + rapid pacing group and Omeprazole + rapid pacing group. The 1:1 rapidest atrial pacing was performed in the latter 2 groups following venous injection of NS and Omeprazole, respectively. Atrial effective refractory period was measured at basic cycle length of 200 and 150 ms before pacing and 0.5,1,1.5, 2, 2.5 and 3 h after the onset of atrial pacing, respectively. The rate adaptability of AERP was analysised at the same time. Results (1) The AERP and the rate adaptability of AERP have no significant changes after intravenous injection of Omeprazole without rapid atrial pacing compared with the baseline. (2) The AERP has no change in NS group in 3 hours with no pacing; In NS+P group, AERP₂₀₀ and AERP₁₅₀ shortened dramatically after rapid atrial pacing, and the peak reached at 2 hour and 1.5 hour of pacing, respectivly. (p<0.05 , compared with the baseline); The AERP shows no remarkable change in OM+P grpup. (3) The rate adaptability of AERP has no change in NS group in 3 hours with no pacing; In NS+P group, the index of rate adaptability was 0.10±0.06 before pacing. With the perpetuation of rapid atrial pacing, the rate adaptability decreased gradually and became negative number inthe 3^rd hour of pacing with the rate adaptability index being -0.03±0.05. (P<0.01); there is no significant change of the rate adaptability in OM+P group. Conclusion Omeprazole do not directly modify the AERP, but can attenuate the pacing-induced AERP shortening.