Background: Selection of the optimal dose of beta-blocker treatment in myocardial infarction (MI) patients is problematic because of a lack of well-established guidelines. Methods: We evaluated changes in synchronization between 0.1 Hz oscillations in heart rate (HR) and plethysmographic peripheral microcirculation in response to a tilt-table test and to 3-month treatment with the highest tolerated beta-blocker (metoprolol) dose in 43 patients aged between 41 and 77 years with acute MI 6 months prior to the start of the study. Before the study the patients were treated with small doses of beta-blocker. Phase differences between HR and peripheral microcirculation oscillations were used to measure the degree of synchronization (S), and relative change in S from horizontal position was used to characterize the response to vertical tilt. Results: Two groups of MI patients matched for clinical characteristics were identified on the basis of the results. The first group was composed of patients with decreased S as a response to vertical tilt at the beginning of the study. The patients with increased S during vertical tilt before treatment with the highest tolerated beta-blocker dose were attributed to the second group. The response to vertical tilt in the first group of patients was postulated to indicate the need to increase beta-blocker dose, and in turn, the response in the second group to indicate an already adequate beta-blocker dose. Conclusion: Assessment of synchronization of 0.1 Hz HR and peripheral microcirculation oscillations as a response to a tilt test can possibly be used as a guideline for selecting beta-blocker dose in post-MI patients.
Journal of Cardiovascular Medicine 2012; 13(8): 491-498

The aim: of this study was to evaluate prognostic value of autonomic regulation indices for the 5-year risk of fatal cardiovascular events in patients after acute myocardial infarction (MI). Methods: We studied 125 patients (53 female) after acute MI aged 30-83 years. The period of observation was 5 years with checkpoints at the first week after acute MI and then annually. Synchronous registration of electrocardiogram (ECG), photoplethysmogram and respiration were made in rest in all patients. The presence of synchronization of 0.1 Hz rhythms in cardiovascular system (CVS) (heart and microcirculation) were determined from the difference of phases. The degree S of 0.1 Hz rhythms synchronization were estimated. Results: We compared prognostic value of different degrees S of synchronization between 0.1 Hz rhythms in CVS for evaluation of the 5-year fatal risk in post-MI patients. S < 20% at the first week after acute MI were identified as the most important factors for evaluation of the risk of 5-year mortality in post-MI patients (χ2 = 10.5, P = 0.005). Sensitivity and specificity of S < 20% at the first week after acute MI were 76% and 43%, respectively. Conclusion: The degree S of 0.1 Hz rhythms synchronization below 20% in post-MI patients is a sensitive marker of high risk of mortality during the subsequent five years.
Journal of Hypertension. 2011. Vol 29. e-Supplement A. P. e528