Vnitr Lek 2003, 49(12):921-926

[The heart in diabetics].

J Bělobrádková, B Filipenský: Diabetologické centrum, Interní gastroenterologická klinika Lékarské fakulty MU a FN Brno.

Macrovascular complications in diabetics create a high risk for cardiovascular disease (CVD). Generally, the main risk factors for CVD include age, men's sex, elevated LDL-cholesterol and reduced HDL-cholesterol, elevated fibrinogen, hypertension, smoking, and diabetes mellitus. Clinical manifestation of coronary disease is determined by number, area, and severity of coronary stenoses, myocardial function, and presence of induced ischemia. Routine pharmacological treatment of ISHD concentrates on risk factors and hasn't been yet focused on changes in energy metabolism during ischemic situation which are important factors contributing to ischemic damage. Substances able to optmize energy metabolism of heart muscle offer a very tempting way both for ISHD treatment and for treatment of following cardiovascular complications. Optimal use of energy source in heart muscle can favour heart activity so that comparable amount of contractile work requires less oxygen. The most beneficial way of getting energy for myocardium while low consumption of oxygen is oxidation of glucose. Because of a large amount of free fatty acids (FFAs) in diabetics a more demanding way of oxidation takes place in them, the oxidation of FFAs. Therefore myocardium of a diabetic needs under normal perfusion conditions more oxygen to provide energy. Besides increase in demand of oxygen, FFAs separate glycolysis from glucose oxidation and increase undesirable production of lactate and protons. An ischemic myocardium of a diabetic has primarily bigger demand of oxygen then myocardium of a non-diabetic. Development of cell ischemia, with all the known consequences in forms of lactate acidosis, calcium overload, and depletion of ATP, leads to considerable contractile disorder. Unfavourable position of metabolic activities in myocardium of diabetics and faster and more serious progression of atherosclerosis result in a big risk of CVD in diabetics. Incidence of coronary events in diabetics without history of ISHD is as big as in non-diabetics with history of coronary events.