We have read the case report of Carpagnano et al entitled “Big atria, little P-waves: unexpected mismatch between chamber volume and electrocardiogram signal in ‘false’ atrial fibrillation” with great interest [1] . The authors reported an elderly patient whose severely enlarged atria (larger than ventricles) and severe mitral regurgitation mismatched with very small P-waves on the electrocardiogram, so small to go unseen at first hasty examination. We have some suggestions related to this issue.