In addition, the serum level of TIMP-1 increased significantly from the SR group to the paroxysmal AF group and then to the persistent AF group as follows: SR group 67.4 (56.9–81.3) ng/ml; paroxysmal AF group 89.7 (70.6–115.5); and persistent AF group 127.3 (87.0–173.7), p  <  0.001. This evidence concerns the gene TIMP1 and Paroxysmal atrial fibrillation.