ADVANTAGES OF MULTI-DAY ECG MONITORING IN DIAGNOSTICS OF LIFE-THREATING ARRHYTHMIAS AND PARAMETERS OF ELECTRIC MYOCARDIAL INSTABILITY IN POST-INFARCTION PERIOD PATIENTS
Background. To conduct a comparative analysis of the quality of life-threatening arrhythmias and markers of myocardial electrical instability detection using 24-hour Holter and long-term ECG monitoring in patients with myocardial infarction with ST segment elevation (STEMI). Materials and methods. The study included 15 patients, aged 56.7 ± 8.9 years, after STEMI. All patients have undergone long-term ECG monitoring (5 days) using the Astroсard Holter ECG monitoring system (HM ECG24) (Meditek, Russia) at the 4-6<sup>th</sup> day and 12 weeks after STEMI. In addition to the standard ECG analysis, additional techniques were analyzed in a semi-automatic mode: the presence of late ventricular potentials were determined, turbulence and heart rate variability were evaluated, and the QT interval and its dispersion were measured. For a comparative analysis of the quality of detection of fatal arrhythmias and parameters of myocardial electrical instability in Holter 24-h and long-term ECG monitoring, a 24-hour ECG was extracted from a 5-day recording using a manual method. Results. The differences were recorded between Holter 24-h and long-term ECG monitoring at baseline when assessing life-threatening rhythm disturbances: 33.3 % and 66.7 % of patients, respectively ( p = 0,03), and at the 12th week after STEMI: 40% and 60 % of patients, respectively ( p = 0,05). Late post-depolarization was recorded more often in patients with long-term ECG monitoring: 40 % versus 6.7 % ( p = 0,036). Pathological turbulence was also more often detected in long-term ECG monitoring: 46.7 % versus 26.7 % ( p = 0,04). By the 12th week of follow-up, the temporal and spectral indicators of heart rate variability had a significant trend to improve when evaluating the records obtained during 5-day ECG monitoring. According to the results of changing the QT interval, the dispersion dynamics of the QTa and QTe intervals was also observed only with prolonged ECG monitoring. Conclusion. An increase in ECG monitoring time allows to identify more accurately and at earlier dates the markers of electrical heterogeneity of the heart muscle, which are predictors of the life-threatening arrhythmias and sudden cardiac death in patients with STEMI.