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Effects of exercise training on heart rate variability in Chagas heart disease
Bruno Ramos Nascimento1, Márcia Maria Oliveira Lima2, Maria do Carmo Pereira Nunes1
1Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Insights
Physical training did not significantly alter heart rate variability (HRV) indexes in Chagas heart disease (CHD) patients. Clinical improvements from exercise in CHD appear independent of autonomic dysfunction markers.
Area of Science:
- Cardiology
- Autonomic Nervous System Research
- Exercise Physiology
Background:
- Heart rate variability (HRV) is a key indicator of autonomic nervous system function and its severity in dysfunction.
- The impact of physical training on HRV in Chagas heart disease (CHD) remains incompletely understood.
Purpose of the Study:
- To investigate the effects of a structured physical training program on HRV indexes in patients with Chagas heart disease and left ventricular dysfunction.
Main Methods:
- A 12-week exercise intervention was conducted over 3 sessions per week.
- Patients with CHD and left ventricular dysfunction, initially inactive, were randomized into an intervention group (N=18) or a control group (N=19).
Main Results:
- While total power and very low-frequency power showed increases in the intervention group, overall delta HRV indexes (SDNN, rMSSD, TP, LFP) were not significantly different between the intervention and control groups.
- High-frequency power showed a trend towards increase in the intervention group (p=0.08).
Conclusions:
- Physical activity variation did not lead to significant differences in HRV index changes between the active and inactive groups in this CHD population.
- Clinical benefits observed with physical activity in CHD patients may not be directly linked to improvements in autonomic dysfunction markers as measured by HRV.
Background:
Heart rate variability (HRV) is a marker of autonomic dysfunction severity. The effects of physical training on HRV indexes in Chagas heart disease (CHD) are not well established.
Objective:
To evaluate the changes in HRV indexes in response to physical training in CHD.
Methods:
Patients with CHD and left ventricular (LV) dysfunction, physically inactive, were randomized either to the intervention (IG, N = 18) or control group (CG, N = 19). The IG participated in a 12-week exercise program consisting of 3 sessions/week.
Results:
Mean age was 49.5 ± 8 years, 59% males, mean LVEF was 36.3 ± 7.8%. Baseline HRV indexes were similar between groups. From baseline to follow-up, total power (TP): 1653 (IQ 625 - 3418) to 2794 (1617 - 4452) ms, p = 0.02) and very low frequency power: 586 (290 - 1565) to 815 (610 - 1425) ms, p = 0.047) increased in the IG, but not in the CG. The delta (post - pre) HRV indexes were similar: SDNN 11.5 ± 30.0 vs. 3.7 ± 25.1 ms. p = 0.10; rMSSD 2 (6 - 17) vs. 1 (21 - 9) ms. p = 0.43; TP 943 (731 - 3130) vs. 1780 (921 - 2743) Hz. p = 0.46; low frequency power (LFP) 1.0 (150 - 197) vs. 60 (111 - 146) Hz. p = 0.85; except for high frequency power, which tended to increase in the IG: 42 (133 - 92) vs. 79 (61 - 328) Hz. p = 0.08).
Conclusion:
In the studied population, the variation of HRV indexes was similar between the active and inactive groups. Clinical improvement with physical activity seems to be independent from autonomic dysfunction markers in CHD.
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