Background: The maze procedure for atrial fibrillation (AF) is effective in restoring sinus rhythm. However, a significant proportion of patients failed to recover atrial mechanical contraction (AMC). We sought to evaluate the preoperative level of atrial transforming growth factor-棺1 (TGF-棺1) mRNA expression would be related to the recovery of atrial mechanical contraction (AMC).
Methods: Preoperative atrial TGF-棺1 mRNA was measured in 128 consecutive patients who underwent mitral valve surgery combined with the maze procedure using cryoablation for persistent AF. Presence of AMC was assessed using Doppler echocardiographic measurement of the transmitral A-wave velocity.
Results: At 1-year follow-up, patients without AMC (n=62) had significantly higher levels of preoperative atrial TGF-棺1 mRNA expression (0.42 versus 0.28, P=0.01) than those with AMC (n=66). When the patients were divided into 3 groups according to TGF-棺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-棺1 mRNA levels were independently associated with the absence of AMC (odds ratio 7.47, 95% CI 1.63 to 34.4, P=0.01). In a subgroup analysis, it was also identified as an independent parameter for the development of atrial electromechanical dissociation, a state in which there is no AMC even in restored sinus rhythm (P=0.002).
Conclusions: Atrial TGF-棺1 mRNA expression was significantly associated with a lack of AMC recovery and with the development of atrial electromechanical dissociation 1 year after the surgical maze procedure for persistent AF.