Digitalization of ECG in optimization of diagnostics of acute and chronic coronary syndromes

Abstract

The aim is to study the additional diagnostic possibilities of indicators obtained by digitalization of ECG in patients with ST-elevation myocardial infarction (STEMI) and stable angina (SA).Material and methods. 135 patients were examined, who were divided into groups depending on the diagnosis: 45 people with STEMI and 90 patients with SA. According to the value of the first derivative of the T wave - the maximum speed ratio (MSR) indicator, patients with STEMI were divided into two groups: group I included 25 people with MSR <0.66, group II - 20 patients with MSR ≥0.66. Patients with SA were also distinguished depending on MSR: group A included 41 patients with MSR <0.87 and group B - 49 patients with MSR ≥0.87. The results of echocardiography, Holter ECG monitoring, coronary ventriculography and digitalization of ECG based on the «Smart-ECG» medical software were evaluated.Results. In the STEMI group, significantly lower MSR values of ischemic zone were noted, compared to the group of patients with SA (0.65±0.02, Δ –25.29%, p<0.001), higher STH values in ischemic zone (0.76±0.04 mm, Δ +58.33%, p<0.001), lower left ventricular ejection fraction (LVEF) (51.96±1.21 %, Δ -9.82%, p<0.001), longer ischemia (919.00 (133, 00; 1310.00) min, Δ +3729.17%, p<0.001), lower standart deviation values of N-N intervals (SDNN) (88.11±6.65 ms, Δ -20.88%, p=0.094). Individuals with SA and MSR <0.87 showed slightly higher values of MSR in lead V2, compared to the group of SA and MSR ≥0.87 (2.51±0.08, Δ +8.19%, p=0.058). In patients with STEMI and MSR <0.66 and with SA and MSR <0.87, compared to the group with STEMI and MSR ≥0.66 and with SA and MSR ≥0.87, lower LVEF were detected (respectively (52.00 (47.75; 55.00) %, Δ -10.34%, p=0.071) and (56.73±0.83%, Δ -3.14%, p=0.088).Conclusions. Primary changes in the repolarization phase, which are inherent for patients with STEMI and SA, cause a change in the speed parameters of the differentiated ECG – reducing of MSR (more intense for patients with STEMI), which indicates a pronounced electrical disbalance of the ischemic myocardium. Lower values of MSR result in worse clinical and functional characteristics of the myocardium for STEMI and SA and are associated with negative prognostic markers of ischemia.