Determination of left ventricular ejection fraction and C-reactive protein by the state of ischemic myocardium - capabilities of ECG digitalization

Aim. To determine the dependence of left ventricular ejection fraction (LVEF) and C-reactive protein (CRP) on the condition of ischemic myocardium considering additional diagnostic data, obtained from differentiated ECG.Material and methods. To achieve the goal, 135 patients with coronary artery disease (CAD) were examined and divided into comparison groups: 48 patients with LVEF <55 % and 87 patients with LVEF >= 55 %. ST-elevation myocardial infarction (STEMI) was diagnosed in 45 of 135 patients, who were grouped according to LVEF: 17 patients with LVEF <50 % and 28 patients with LVEF >= 50 %. Stable angina (SA) was documented in 90 of 135 patients, who were assigned to groups depending on LVEF: 51 patients with LVEF <60 % and 39 patients with LVEF >= 60 %. Depending on the CRP level, 2 SA groups numbering 46 people were formed: 18 patients with a level of CRP >= 0.5 mg/dL and 28 patients with a level of CRP <0.5 mg/dL. The study included clinical examinations, questionnaire, analysis of biomarkers and data of functional methods of examination (echocardiography, coronary ventriculography, ECG digitalization with the assessment of its parameters based on the "Smart-ECG" medical software platform).Results. Patients with CAD and LVEF<55 % had higher values of endothelin-1 (ET-1) (10.21 (7.69; 11.65) pg/ml, Delta +41.81 %, p = 0.040), slightly higher levels of CRP (0.53 (0.35; 0.70) mg/dL, Delta +51.43 %, p = 0.124), lower the maximum speed ratio (MSR) (0.71 +/- 0.03, Delta -15.48 %, p = 0.004), but a greater height of the ST-slope (STH) in the ischemic zone on the differentiated ECG (0.65 +/- 0.04 mm, Delta +25.00 %, p = 0.022), than those in patients with LVEF >= 55 %. In the STEMI group with LVEF <50 %, slightly higher STH values were noted during the period of maximum elevation of the ST segment on the differentiated ECG (2.51 (1.90; 3.16) mm, Delta +30.05 %, p = 0.060) as compared to the group with LVEF >= 50 %. SA patients with LVEF <60 % had a tendency to higher levels of CRP (0.50 (0.29; 0.67) mg/dL, Delta +51.52 %, p = 0.076) and ET-1 (9.15 (7.00; 11.18) pg/ml, Delta +28.69 %, p = 0.075) in comparison with LVEF >= 60 % group. Patients with SA and a CRP level >= 0.5 mg/dL had higher ET-1 values (10.83 (9.94; 12.64) pg/ml, Delta +58.10 %, p < 0.001), lower values of MSR on the differentiated ECG in the ischemic zone (0.63 (0.52, 0.74) , Delta -41.12 %, p = 0.001) as compared to those in the CRP <0.5 mg/dL group. The negative direction of the T wave and various types of rhythm disturbances in SA patients led to more significant decrease in MSR indicator of the differentiated ECG.Conclusions. Values of LVEF <55 % in CAD, LVEF <50 % in STEMI, LVEF <60 % in SA, CRP >= 0.5 mg/dL in SA are associated with worse indicators of clinical, laboratory and instrumental methods of examination that allow to describe the condition of ischemic myocardium, and the ECG digitalization based on the medical software "Smart-ECG" allows to expand the diagnostic capabilities.