Heart-type fatty acid-binding protein (H-FABP) is a non-invasive bio-marker, with high sensitivity and specificity, being capable to point out the myocardial injury and to predict major adverse cardiovascular events (MACE). Cardiac rehabilitation program, through a complex and sustained post-interventional management plays an important role in reducing the plasma levels of H-FABP. In the study, which included 120 post-coronary artery bypass (CABG) patients, we analyzed the link between low levels of general post-surgical health status and the presence of cardiovascular risk factors, common biochemical markers, and especially the role played by diabetic status in lowering the plasma H-FABP levels. From the group, 65 patients had been diagnosed with type 2 Diabetes Mellitus (T2DM). The H-FABP values decreased both in diabetics and in non-diabetics between the two phases of CR, 6 months away from CABG. More than half of the patients had important reduction of H-FABP, at 6 months after the onset of CR program. Half of the group registered a smaller reduction of H-FABP, but more noticeable in diabetics. Ischemic lesion during open heart surgery is linked to high levels of H-FABP and with an occurence risk of postoperative atrial fibrillation, that can be also triggered and sustained by multiple endocrine conditions related to aging. Thus, metabolic control should always remain a target of the complex management in cardiac rehabilitation.