This study aims to identify the clinical and laboratory variables that can predict the development of AF, ascertain whether the serum levels of sST2 and TIMP-1 are different between patients with SR and those with AF, observe whether sST2 and TIMP-1 are related to the progression of AF, and, if so, determine the cutoff point of sST2 for predicting such progression. Here, TIMP1 is linked to atrial fibrillation.