[Heart pathology of extracardiac origin. XI. Cardiac repercussions of diabetes mellitus].

Diabetes mellitus is one of the diseases with the greatest risk of developing coronary disease (CD), with the estimation of this risk in relation to the general population being from 2 to 4-fold greater. The existence of diabetes worsens the prognosis of CD and thus, postinfarction mortality in these patients is double that observed in non-diabetic patients. Together with the risk factors found in the general population, those of special interest are those derived from diabetes itself, such as hyperglycemia, dyslipemia, coagulation disorders and hyperinsulinemia or insulin resistance. Among these, the most important is probably the hyperglycemia which may contribute to the appearance of CD by different mechanisms such as proteic glycosylation, accumulation of sorbitol, increase in the synthesis of protein kinase C or oxidative stress. It must not be forgotten that an old controversy has recently been brought up suggesting that sulphonylureas may have a certain cardiotoxic effect, probably acting on the potassium channels dependent on ATP. Acute myocardial infarction in diabetic patients carries a greater risk of congestive heart failure, recurrent infarction, arrhythmia and cardiogenic shock, with one of its characteristics being the possibility of being silent when autonomic neuropathy is present. The prognosis of CD may be markedly improved by obtaining optimum glycemic control during the hours following infarction using intensified treatment. Diabetic myocardiopathy as a differentiated nosology responsible for alterations in myocardial contractile function and greater prevalence of heart failure in these patients seems to be clearly demonstrated although its etiology remains unknown.