Effect of renal sympathetic denervation on the progression of paroxysmal atrial fibrillation in canines with long-term intermittent atrial pacing

AIMS: The aim of the present study was to explore the effect of renal sympathetic denervation (RSD) on the progression of paroxysmal atrial fibrillation (AF) in canines with long-term intermittent atrial pacing. METHODS AND RESULTS: Nineteen beagles were randomly divided into sham-operated group (six dogs), control group (six dogs), and RSD group (seven dogs). Sham-operated group were implanted with pacemakers without pacing; control group were implanted with pacemakers with long-term intermittent atrial pacing; and RSD group underwent catheter-based RSD bilaterally and were simultaneously implanted with pacemakers. Atrial pacing was maintained for 8 h a day and a total of 12 weeks in the control group and RSD group. Echocardiography showed that the left atrial structure and function were significantly improved in the RSD group compared with the control group (P < 0.05). Compared with the control group, the RSD group had fewer incidences of AF and a shorter duration of AF (P < 0.05) after long-term intermittent atrial pacing. In addition to increased atrial effective refractory period (AERP) and AF cycle length, AERP dispersion and P-wave duration and dispersion were significantly decreased in the RSD group compared with the control group (P < 0.05). Atrial morphological evaluation suggested that fibrosis and ultrastructural changes induced by long-term intermittent atrial pacing were markedly suppressed in the RSD dogs compared with controls (P < 0.05). Immunohistochemistry results showed that connexin 43 distribution in RSD mid-myocardial was significantly fewer heterogeneous than that in control mid-myocardial (P < 0.05). CONCLUSION: Renal denervation inhibits the progression of paroxysmal AF, which might be related to the suppression of atrial electrophysiology and structural heterogeneity.