The impact of effective therapy with atorvastatin on the dynamics of parameters of electrical instability in patients with st-elevation myocardial infarction

Abstract

Aim. To assess the dynamics of parameters of myocardial electrical instability in patients with ST-elevation (STE) myocardial infarction (MI) treated with various doses of atorvastatin. Materials and methods. Patients with STEMI (n=70), who received atorvastatin 20 or 80 mg/day for 48 weeks, were divided into two groups: group "E"-38 patients (54.3%) in whom by 48-th week target values of low density lipoprotein cholesterol (LDLC) were achieved, and group "NE"-32 patients (45.7%) in whom these levels were not achieved. On days 7-9, at 24th and 48th weeks after onset of MI the patients underwent 24-hour 12-Ieads ECG monitoring with subsequent analysis of parameters of myocardial electrical inhomogeneity: late ventricular potentials (LVP), dispersion of QT-interval duration, heart rate variability (HRV) and turbulence. Results. After of treatment with atorvastatin target value of LDLC was achieved in 73.5 and 36.1% of patients receiving 80 and 20 mg/day, respectively. In the group "E" we observed positive dynamics of LVP parameters (QRSf-p<0.01, HFLA-p<0.001, RMS-p<0.05), decreases of QTa disp (p<0.05) and sdQJa (p<0.01), favorable transformation of HRV temporal (SDNNi, pNN50-p<0.05, RMSSD, TINN-p<0.0l) and frequency indices (Hip, L/H-p<0.00l). Most striking evolution in this group referred to HRV during night hours. Conclusion. Atorvastatin induced achievement of target LDLC values decreased myocardial arrhythmic readiness what was reflected by reduction of frequency of LVP registration and dispersion of QT duration, increase of activity of the parasympathetic link of vegetative regulation of cardiac activity.