Objective To investigate the electrophysiological characteristics and atrial structures in the canine models of persistent atrial fibrillation (AF) prepared with rapid pacing of pulmonary vein.Methods Thirty canines were randomly divided into experimental group (n=15) and control group (n=15).Canines in experimental group underwent persistent pacing of pulmonary vein (PV) at 20 Hz to induce AF model (>24 h).Biatrial areas were measured using two-dimensional echocardiography before and after rapid pacing of PV.Six mapping electrodes patches were used to record the electrophysiological characteristics of four PVs,left atrium (LA) and right atrium (RA).Effective refractory period (ERP) and atrial fibrillation cycle length (AFCL) were also measured.Results Persistent AF (>24 h) was successfully induced in 11 canines in experimental group within (28.2±3.0) d.At the end of the pacing period,biatrial areas were enlarged significantly 〔LA:(6.9±1.1) cm2 vs (11.7±1.6) cm2 (P<0.001);RA:(4.3±0.8) cm2 vs (7.0±1.2) cm2 (P<0.001),respectively〕.Compared with the control group,the ERP of atriums and four PVs in the experimental group were shortened significantly.There was also an ERP/AFCL gradient on different positions in experimental group after pacing.ERP/AFCL in the RA free wall was significantly longer than that in the PVs and LA free wall (P<0.05).Conclusion In canine model of persistent AF induced by rapid pacing of PV,the changes of electrophysiological characteristics and atrial structures may be involved in mechanism of persistent AF.?更多