Features of Holter ECG monitoring indicators and structural and functional cardiac remodeling in patients with Q-wave myocardial infarction in the acute period after primary coronary intervention

Abstract

Aim. To identify the features of Holter ECG monitoring indicators and structural and functional cardiac remodeling in patients with Q-wave myocardial infarction (Q-MI) in the acute period after primary coronary intervention (PCI).

Materials and methods. In total, 78 patients with acute Q-MI were divided into 2 groups: group 1 – patients (n = 42) who underwent PCI during the acute period of Q-MI (median age 62 (52; 71) years); group 2 – patients (n = 36) who received standard pharmacological therapy (median age 67.5 (61.5; 75.0) years).

Results. The mean corrected QT interval (QTc) was 404 (391; 423) ms and 418 (397; 445) ms in groups 1 and 2, respectively. Group 1 demonstrated a significantly lower incidence of left ventricular (LV) akinesia (14 vs. 21 cases, p = 0.03), a significantly higher number of patients with normal ejection fraction (EF) (30 vs. 19, p = 0.01), and fewer patients with reduced EF (1 vs. 8, p = 0.01). A trend toward a shorter QTc was observed in group 1 (by 3.35%, p = 0.05). QTc duration correlated with the number of ST-segment episodes (r = 0.36, p < 0.05), the duration of tachycardia episodes (r = 0.37, p < 0.05; r = 0.43, p < 0.05), the number of premature ventricular contractions (PVCs) during the day and night (r = 0.52, p < 0.05; r = 0.51, p < 0.05), and the number of single and paired PVCs (r = 0.49, p < 0.05; r = 0.45, p < 0.05). The presence of LV akinesia correlated with episodes of supraventricular arrhythmias (r = 0.35, p < 0.05), while the presence of LV aneurysm correlated with the number of PVCs during both daytime and nighttime periods (r = 0.35, p < 0.05; r = 0.38, p < 0.05). In both groups, patients with significantly or moderately reduced heart rate variability (HRV) were observed: 13 vs. 16 (p = 0.2). In both study periods, an increase in the relative value of the very low frequency (VLF) component (>30 % of total power, TR) and a decrease in the high-frequency (HF) component (<15 %) were noted. The number of patients with RMSSD <20 ms was similar between groups: 19 (45 %) vs. 16 (44 %), p = 1.0.

Conclusions. In all patients with acute Q-MI, regulatory system tension was observed, characterized by predominance of the sympathetic component of HRV. A high proportion of the VLF component in total power indicated elevated psycho-emotional stress levels. Patients receiving standard pharmacological therapy demonstrated QTc prolongation and reduced autonomic nervous system flexibility compared with PCI-treated patients. In patients after PCI, the number of PVCs and ischemic episodes showed a direct relationship with QTc duration. Moreover, these patients had significantly fewer cases of LV akinesia, a greater number of patients with normal EF, and fewer cases of reduced EF compared with the drug therapy group.