Objectives: The aim of this study was to determine the relationship between the complexity of coronary artery disease and pro-inflammatory factors in the form of anticardiolipin antibodies, as well as to determine the relationship between global left ventricular systolic function and mitochondrial respiration parameters. Materials and methods: An observational, cross-sectional, clinical research was conducted. A total of 65 adult patients who underwent invasive coronary angiography due to suspected coronary artery disease (first study) and 40 adult patients who underwent elective surgical myocardial revascularization due to significant coronary artery disease (second study) were included. All subjects underwent a detailed medical history, physical examination and echocardiographic measurements. Subjects from the second study underwent intraoperative myocardial biopsy, which was followed by subsequent experimental assessments of mitochondrial function in biopsied myocardial tissue. Results: An independent statistically significant positive correlation of the complexity of coronary artery disease (SYNTAX score) and anticardiolipin antibody aCL-IgG was determined (β 5.58, P=0.005), while there was no such association for other selected variables (aCL-IgG, leptin, C3, C4) after adjusting for age, body mass index, glucose and cholesterol levels. Furthermore, a statistically significant positive correlation was found between maximal mitochondrial respiration in myocardial tissue and left ventricular ejection fraction (r=0.37, P=0.020), which was confirmed after adjustment for confounding variables (β 0.11, P =0.030). Similarly, a statistically significant positive correlation was found between the left ventricular ejection fraction and the expression of the main fatty acid oxidation enzymes. On the other hand, no significant correlation was found between cardiac systolic function and indicators of mitochondrial quantity in the tissue, nor the level of individual respiratory complexes. Also, no significant correlation was found between cardiac systolic function and mitochondrial capacity for carbohydrate oxidation. Conclusions: Anticardiolipin aCL-IgG antibody levels are significantly related to the complexity of coronary artery disease in the form of SYNTAX score, while the same relationship does not exist with other mediators of inflammation such as anticardiolipin antibody aCL-IgM, complement components C3 and C4, and leptin. Also, in patients in the early stages of pathological remodeling of the myocardium and slightly reduced systolic function, there is a relationship between LVEF and mitochondrial respiratory ability and fatty acid oxidation capacity.