Due to the variability that exist in the patient population between the different studies, differences in the therapies followed by the patients (some authors have proposed that angiotensin-converting enzyme inhibitors have a direct effect on cardiac remodelling and energy metabolism [48]) or in the clinical characteristics of the individuals (specially metabolic disorders such as diabetes; to note, we have selected for this study only non diabetic patients) could account in part for those controversial results. This evidence concerns the gene ACE and diabetes mellitus.