Search

Influence of Atrial Fibrosis on the Efficacy of Radiofrequency Maze Procedure in Patients with Rheumatic Heart Disease and Permanent Atrial Fibrillation

Abstract： Objectives To determine the atrial expression of the collagen Ⅰ, collagen Ⅲ and the transforming growth factorbeta 1 (TGF-β1) in patients with rheumatic heart disease (RHD) and permanent atrial fibrillation(PAF) and to investigate the relationship between the extent of atrial fibrosis and the effectiveness of radiofrequency maze procedure in patients with RHD and PAF. Methods A total of 40 patients with RHD and PAF (≥6 months) who underwent a radiofrequency maze procedure with concomitant valvular surgery were collected for the experimental group. We acquired 100 mg of the left auricle tissue in each patient and followed up these patients after 3, 6 months of [CM(158mm]surgery. Then we assigned these patients to nonAF group and persistent AF group according to the results of the 6month followup. Another 10 patients with RHD and sinus rhythm(SR) who underwent valvular surgery alone were assigned to SR group and their left auricle tissue was also obtained. In order to determine the extent of atrial fibrosis, we observed the amount of collagen volume fraction Ⅰ，Ⅲ(CVF-Ⅰ,CVF-Ⅲ) by semiquantitative analysis with picrosirius red staining method. Using the β actin protein as the endogenous reference gene, we detected the expressions of TGF-β1 mRNA by semiquantitative reverse transcriptionpolymerase chain reaction(RT-PCR) technique. Results Each group has the same clinical baseline. At 6month follow-up, 28 among the 40 patients were categorized into the nonAF group and 12 into the AF group. (1) Patients in the nonAF group and the AF group had higher mRNA expressions of TGF-β1, CVF-Ⅰ and CVF-Ⅰ/CVF-Ⅲ compared with the SR group (F=6.487, P=0.003; F=3.711, P=0.032; F=3.697, P=0.032). The AF group had higher mRNA expressions of TGF-β1, CVF-Ⅰ and CVF-Ⅰ/CVF-Ⅲ than the nonAF group (t=4.372, P=0.043; t=4.603, P=0.038; t=4.776, P=0.035). But the CVFⅢ had no significant differences among the three groups (P＞0.05). (2) The patients whose left atrial function recovered after Maze procedure had lower mRNA expression than those patients whose left atrial function did not recover in the nonAF group (t=5.570, P=0.027). (3) The TGF-β1 mRNA expression has a positive correlation with both the contents of CVF-Ⅰ and left atrial diameter (r=0.786, Plt;0.05; r=0.858, Plt;0.05). Multiple logistic regression analysis revealed that the mRNA expression levels of TGF-β1, CVF-Ⅰ and left atrial diameter were independently associated with the postoperative persistence of atrial fibrillation. Conclusion The extent of atrial fibrosis in patients with RHD and PAF may be related to the sinus rhythm restoration and maintenance after AF surgical radiofrequency ablation and the resumption of atrial function.