In this way, we could hypothesize that increased LA and peripheral relaxin-2 plasma levels in AF patients who presented sinus rhythm in the study, could be exerting the multiple beneficial cardioprotective effects during pathological events (AF in this case) that have been described for this molecule, and that include suppression of arrhythmia and inflammation, reversal of fibrosis or amelioration of oxidative stress19,20. This evidence concerns the gene RLN2 and cardiac arrhythmia.