Session P36.1

Prognostic Value of the Time Related Autonomic Balance Indicator for Risk Evaluation of Cardiovascular Events in Patients with IHD

M Matveev*, R Prokopova

Bulgarian Academy of Sciences
Sofia, Bulgaria

Objectives: In our previous studies we indicated that: i) the various CVD (AH, CHF) have a different circadian profile of heart autonomic balance (HAB), compared to the profile in healthy subjects; ii) the restoration of normal circadian characteristics of the HAB decreases the cardiac risk in these patients. In this study we analyze the specific abnormalities in HAB circadian changes in three groups of patients with ischemic heart disease (IHD), and prognostic value of these circadian profiles for risk evaluation of cardiovascular events (CVE).
Methods: The study comprised of 26 patients with unstable angina (UA) (without CVE within the framework of one year – i.e. with good prognosis); 15 patients with morning MI (MMI), and 19 patients with MI in the non-morning hours (NMMI). The patients are without diabetes or other severe system diseases, conduction disorders, frequent arrhythmias and anti-arrhythmic therapy. The HAB changes were assessed by HRV indices from ECG recordings in resting state (RS) and by parasympathetic (Valsalva manoeuvre; VM), or sympathetic (handgrip test; HT) stimulation. In Computers in Cardiology 2003:30 we proposed the Time Related Autonomic Balance Indicator (TRABI) – a non-parametric criterion for estimating the changes in HAB by any HRV indices. In this study, TRABI was used for evaluation of the specific changes in HAB in the three patient groups.
Results: The mean value of TRABI for the HRV indices in the study in RS versus HT in healthy subjects is 0, 100; in patients from the three groups this value, respectively, is: with UA 0, 180 (n.s.); with MMI 0, 177 (p=0, 0256); with NMMI 0, 082 (n.s.). The mean value of TRABI in the study in RS versus VM in healthy subjects is 0, 147; in patients this value, respectively, is: with UA 0, 211 (n.s.); with MMI 0, 107 (n.s.); with NMMI 0, 053 (p=0, 0016).
Conclusions: The results indicated that: i) in patients with UA the sympathetic component in HAB is more time-dependent than in healthy subjects; the parasympathetic circadian characteristic is analogous to the normal one. During stress, the vagus performs a protective role and thus secures a favorable long-term prognosis; ii) in the patients with MMI we found abnormal circadian characteristics of HAB with sympathetic hyper-activity and normal parasympathetic tone. The sympathetic dysfunction during stress is probably the reason for the morning peak in the frequency of CVE; iii) in patients with NMMI the circadian nature of the sympathetic activity is preserved, but the circadian changes of the parasympathetic activity are almost absent.

(Abstract Control Number: 14)