The incidence and prevalence of these diseases are increasingly globally, and although more research is needed to elucidate its role in pathologies such as atrial fibrillation, we have observed that an extensive bibliography highlights the contribution of the GIRK1/4 heterotetrameric isoform in heart rate regulation and electrical activity control, and also that this isoform has been linked to cardiac alterations. The gene discussed is KCNJ3; the disease is atrial fibrillation.