Differences in the Force-Interval. Relationship of Isolated Human Myocardium with Chronic Coronary Artery Diseasein Patients with and without Type 2 Diabetes Mellitus and the Role of Ca²⁺-ATPase of Sarcoplasmic Reticulum.

We studied the force--interval relationship of human myocardium in coronary artery d isease (CAD) and CAD with concomitant diabetes mellitus and evaluated its dependence on the level of expression of Ca²⁺-AT Pase of the sarcoplasmic reticulum (SR). We used the myocardial biopsies obtained during coronary artery bypass grafting with the use of cardiopulmonary bypass techniques. The study included patients with chronic CAD and patients with CAD and concomitant type II diabetes mellitus. It was found that patients with CAD with and without diabetes with similar clinical signs had both negative and positive dynamics of the force-interval relationship. The positive. force-interval relationship was associated with the ''high level" of Ca²⁺-ATPase, while the negative force-interval relationship was associated with the "low level" of this protein. In cases of small CAD and diabetes duration, the positive "force-interval" relationship is more pronounced and corresponds to a higher level of expression Ca²⁺- ATPase in the SR than in case of CAD without diabetes mellitus.