The influence of the combined aerobic training to the changes of autonomous modulation at the ill patients after the acute myocardial infarction

Objective of the study:
The autonomous dysfunction is present at the most ill patients after the acute heart attack and is defined by the changes of the sympato-vagální balance that is indicated by the decrease of the variability of the heart frequency (HRV) and the reduced baroreflex sensitivity. The presented work concentrated on the evaluation of the effect of the combined aerobic training and the strength exercise for the changes of the modulation of the autonomous nerve system in the short run by the evaluation of the 8week physiotherapy programme and in the long run of the 12 months after the finished physiotherapy.


The patients and the methods:
81 patients (15 women, 66 men) at the age of 58 ± 9 years after their past first heart attack were by the authors included to the monitoring. The patients were before and after the physiotherapy and after a year examined by the echocardiography, spiroergometric, the short-term frequency and time analysis HRV with the manoeuvre lying position - stand-lying position was performed. The indicators of the frequency domain were evaluated: total spectral performance (TP), LF component (low frequency), HF (high frequency), their ratio LF/HF and the indicator of the time domain MSSD (mean squared successive difference).

Results:
The physiotherapy programme resulted in the significant increase of the values of the high-frequency component (HF) in lying position (p < 0.01), total spectral performance (TP) in lying position (p < 0.05) and the time analysis component (MSSD) (p < 0.05). The significant changes remain after a year and in addition to that the values of the low-frequency component (LF) in lying position (p < 0.01) decreased statistical significantly and so the index LF/HF in lying position (p < 0.05) decreased. At the patients with the higher training activity during the year after the physiotherapy (n = 57) the significantly higher value of the stress tolerance (TZ) and pVO₂ (p < 0.05) was founded out in comparison with the group with the low intensity of physical activity (n = 24). This subgroup had also significantly lower indicators of heart frequency variability MSSD (p < 0.01), TP (p < 0.05) and LF/HF index in lying position (p < 0.02). In the subgroup with lower intensity of physical activity there were more patients with diabetes and combination of hypertension and diabetes, but less patients with eject fractionation (EF) < 50%. The authors founded out the negative relation between the presence of hypertension and diabetes and vag activity indicators, the positive correlation to the cardiopulmonal performance indicators (TZ, pVO₂) and they did not find out the relation to EF. The presence of hypertension and diabetes negatively affected the adjustment of the autonomous nerve system after the physiotherapy.

Conclusion:
The combined aerobic training with strength factors led to the positive change of sympatic-vagal balance at many patients after the heart attack. This adjustment of the autonomous nerve system in favour of vag activity remains in case of the lifestyle change connected with the regular long-term physical activity after a year as well. The factors that determine the changes of HRV after the heart attack have a complex character and reflect both injury of the heart innervation by ischemia and necrosis, the size of the heart attack centre, the dysfunction of the left heart ventricle, neurohumoral activation, and the presence of hypertension and diabetes. For this reason at some patients, the adjustment of the autonomous nerve system in conditions of the made training need not to come.

Keywords: acute heart attack; early physiotherapy; variability of the heart frequency