Atrial TGF-β 1 Expression and Recovery of Atrial Contraction after Maze Procedure

Background:The maze procedure for atrial fibrillation (AF) is effective in restoring sinus rhythm, however, significant proportion of patients failed to recover atrial mechanical contraction (AMC). We hypothesized that preoperative level of atrial transforming growth factor-β 1(TGF-β 1) mRNA expression would be related to recovery of AMC. Methods and Results: Preoperative atrial TGF-β1 mRNA was measured in 128 consecutive patients who underwent the mitral valve surgery combined with maze procedure with cryoablation for persistent AF. Presence of AMC was assessed using Doppler echocardiographic measurement of the transmitral A-wave velocity. At one year follow-up, patients without AMC (n=62) had higher levels of atrial TGF-β 1 mRNA expression (P=0.01) and more extensive atrial fibrosis than those with AMC (n=66). When the patients were divided into 3 groups according to the TGF-β 1 mRNA level, the recovery rate of AMC and the increment of A-wave velocity gradually decreased from the lowest to the highest patient group. Multiple logistic regression analysis revealed that TGF-β1 mRNA level was independently associated with the postoperative absence of AMC (odd ratio 7.47, 95% CI 1.63-34.4, P=0.01). Conclusions: Atrial TGF-β 1 mRNA expression was significantly associated with no recovery of atrial mechanical activity one year after the maze procedure using cryoablation.