Differences in the force–interval relationship of isolated human myocardium with chronic coronary artery disease with and without type 2 diabetes mellitus and the role of sarcoplasmic reticulum Ca2+-ATPase

The dynamics of the force–interval relationship of the human myocardium in coronary artery disease (CAD) and CAD with concomitant diabetes mellitus was studied, and its dependence on the level of sarcoplasmic reticulum (SR) Ca 2+ -ATPase expression was evaluated. The study was performed on myocardial biopsy material obtained during coronary bypass operation using cardiopulmonary techniques. Patients with chronic CAD and patients with CAD associated with type II diabetes mellitus were enrolled in the study. It was found that CAD patients with and without diabetes mellitus with similar clinical parameters had either negative or positive dynamics of the force–interval relationship. The positive force–interval relationship was associated with a “high level” of Ca 2+ -ATPase, while the negative force–interval relationship was associated with a “low level” of this protein. In CAD associated with diabetes mellitus of short duration, the positive dynamics of the force–interval relationship is more pronounced and corresponds to a higher level of SR Ca 2+ -ATPase expression than in CAD alone.