Figure 1: Participant flow chart. Initially, in the first stage of the study (a), 180 eligible hyperthyroidism patients with paroxysmal atrial fibrillation were randomized into either Wenxin Keli (91 cases) or sotalol (89 cases) treatment for sinus rhythm restoration. At the end of the first stage intervention, 83/91 cases and 80/89 cases were reverted to sinus rhythm, respectively. There were 8/91 cases and 9/89 cases who did not restore sinus rhythm. These 17 patients (still with atrial fibrillation) were not eligible for the second part of the study, and they were dropped out. In the second stage of the study (b), all sinus rhythm reverted patients (163 cases) were randomized into one of the following three groups: WK (54 cases), sotalol (54 cases), and control (55 cases) groups. The purpose is to observe drug’s sinus rhythm maintenance effect. At the end of the second stage intervention, 1/54 cases, 2/54 cases, and 9/55 cases had recurrent paroxysmal atrial fibrillation, respectively.