Studies have shown that patients with AF have higher atrial natriuretic peptide (ANP) levels compared with patients in sinus rhythm, and elevated ANP levels have been shown to predict the development of paroxysmal AF in patients with congestive heart failure (Yamada et al., 2000) or following cardiac surgery (Yilmaz et al., 2006). The gene discussed is NPPA; the disease is congestive heart failure.