Prognostic value of the Time Related Autonomic Balance Indicator for risk evaluation of cardiovascular events in patients with ischemic heart disease

The study comprised patients with unstable angina (UA), morning (MMI) and non-morning myocardial infarction (NMMI). The heart autonomic balance (HAB) circadian changes were assessed by time related autonomic balance indicator - a non-parametric criterion for estimating the balance by HRV indices from ECG recordings in rest and by parasympathetic or sympathetic stimulation. The results indicated that: i) in patients with UA the sympathetic part in HAB is more time-dependent than in healthy subjects; the vagal circadian characteristic is normal and thus secures a favorable long-term prognosis; ii) in patients with MMI circadian characteristics of HAB consist of sympathetic hyper-activity and normal parasympathetic tone. The sympathetic dysfunction is the reason for the morning peak of CVE; iii) in patients with NMMI the circadian nature of the sympathetic activity is preserved, but the parasympathetic activity are almost absent.