HRV in cardiac pathology
THE INFORMATIVE VALUES OF HEART RATE VARIABILITY,
HEMODYNAMICS AND OXYGEN UPTAKE FOR OPTIMISATION OF THE
EXERCISE TRAINING PROGRAMME
Institute Psychophysiology & Rehabilitation c/o Kaunas University of Medicine, Palanga,
4 Vydūno Str., Palanga 5720, Lithuania, E-mail: firstname.lastname@example.org
Risk stratification after myocardial infarction identifying patients at a high, intermediate and low risk for sudden death or reinfarction is an established principle for the management of the patients after MI and for the optimisation of training programmes during cardiac rehabilitation.
The aim of this study is to assess the peculiarities of heart rate variability (HRV), hemodynamics and oxygen uptake data during functional testing procedures in post - MI patients at various risk groups and to use them for the optimisation of the intensity of exercise training programme.
Methods. Clinical investigation, followed by typical instrumental (ECG, echocardiography etc.) was performed for every patient at the beginning of search. A computerised power spectral analysis of heart rate variability, hemodynamics and oxygen uptake parameters during an active orthostatic test (AOT), bicycle exercise test or a spiroergometric test were estimated.
The contingent. Investigated were 558 pts after myocardial infarction (age 59.2 yrs). Thus, Q wave MI was in 57,6; pts, without Q wave MI – in 42,4; pts. According to the NYHA
classification, 40 pts were in NYHA class I, 282 pts in NYHA class II and 236 pts – in NYHA class
III. The spiroergometric test was performed in 90 post - MI pts.
The peculiarities and significance of heart rate variability, hemodynamics and O uptake data 2
were assessed in 558 post - myocardial infarction patients, devided into low (44 pts), intermediate (221 pts) and high (293 pts) risk groups.
Rezults. On the ground of our results, we established that in the post - myocardial infarction patients at high risk for acute coronary events, increased baseline heart rate, incompetent HR response to the AOT and bicycle ergometry, depressed HR variability (SDNN < 30 ms, RA < 25 ms), due to reduced parasympathetic HR control and increased humoral one (VLFC ; > 70 ;), and the
predominance of adrenergic vasoconstrictor influence (TPR) are characteristic. Reduced work capacity (kGm, MET) and diminished RPP response, (p < .05) and an insufficient decrease in TPR were established in the high and intermediate risk patients(p < .05). Our data show that in the high
risk post - MI patients, a reduced hemodynamic response to workload is accompanying of diminished cardiovascular functional reserve within an increased impact of sympathetic and humoral HR control. The peak VO consumption values during workload were significantly lower (p < .05) 2
and the oxygen uptake values at the anaerobic threshold (ATVO), O pulse at peak load were lower 22
and the level of VE/VCO higher, in the high risk patients (p < .05). 2
Determinated more informative parameters of autonomic HR control, hemodynamics and O2
uptake were used in preparing an algorithm for the optimisation of intensity of the exercise training programme for the post - MI pts with a different risk level to training.
Conclusions. Increased baseline heart rate, depressed heart rate variability on account of diminished parasympathetic and intensified neurohumoral HR control was established for the high risk post - myocardial infarction patients. Lower physical capacity, a reduced hemodynamics level at rest and a decreased chronotropic, hemodynamic and oxygen uptake responses to workload were determined for the high and intermediate risk post - myocardial infarction patients. On the ground of the informative parameters of autonomic HR control, hemodynamics and O uptake responses to the 2
workload, an algorithm for the optimisation of an exercise training programme was proposed and used for training the CAD pts.