Does the expression of transforming growth factor β-1: affect the outcome of the radiofrequency modified maze procedure in patients with rheumatic atrial fibrillation?

We investigated whether the expression of transforming growth factor β-1 in the left atrial appendage affected the outcome of the radiofrequency modified maze procedure in patients with rheumatic valve disease and long-standing persistent atrial fibrillation.Messenger RNA and protein expression of transforming growth factor β-1 and volume fractions of collagen types I and III were measured in 80 patients with rheumatic valve atrial fibrillation who underwent valve surgery with the radiofrequency modified maze procedure; the same was done in a control group of 20 patients with rheumatic valve disease and sinus rhythm who underwent valve surgery alone.At 6 months' follow-up, atrial fibrillation recurred in 24 of the 80 patients in the study group. The messenger RNA and protein expressions of transforming growth factor β-1, collagen type I volume fraction, and left atrial dimension had increased gradually in the control group and in the study subgroups that maintained sinus rhythm or relapsed into atrial fibrillation (P <0.05). The messenger RNA and protein expressions of transforming growth factor β-1 correlated positively with collagen type I volume fraction (r=0.723, P <0.001 and r=0.745, P <0.001, respectively) and left atrial dimension (r=0.762, P <0.001 and r=0.765, P <0.001, respectively). In the sinus rhythm-maintained subgroup, the patients who regained functional atrial contraction had lower messenger RNA and protein expression of transforming growth factor β-1 than did the patients who failed to retain such function (P <0.05).We conclude that the expression of transforming growth factor β-1 in the resected left atrial appendage affects the recurrence of atrial fibrillation and restoration of functional left atrial contraction after the radiofrequency modified maze procedure.