Regarding the usefulness of relaxin-2 as a biomarker for risk stratification in the management of AF, serum relaxin-2 levels were higher in patients with than without AF recurrence, and elevated relaxin-2 serum levels were an independent predictor of post-radiofrequency catheter ablation (RFCA) AF recurrence (Table 3) [119]. The gene discussed is RLN2; the disease is atrial fibrillation.