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Abnormalities in fractal heart rate dynamics in Chagas disease.
Marcos Roberto de Sousa1, Heikki V Huikuri, Federico Lombardi
1Hospital das Clínicas and Internal Medicine Department, School of Medicine, Federal University of Minas Gerais, Minas Gerais, Brazil. mrsousa@ufmg.br
Summary
Fractal heart rate dynamics are altered in Chagas disease patients, indicating early autonomic dysfunction. Impaired left ventricular function shows more random heart rate patterns, potentially due to frequent ventricular premature beats (VPBs).
Area of Science:
- Cardiology
- Autonomic Nervous System Function
- Complex Systems Analysis
Background:
- Chagas disease can lead to autonomic dysfunction and left ventricular (LV) dysfunction.
- Fractal analysis of heart rate (HR) dynamics offers insights into autonomic control.
Purpose of the Study:
- To investigate fractal HR dynamics using detrended fluctuation analysis (DFA) in Chagas disease patients.
- To correlate these dynamics with LV ejection fraction and ventricular premature beats (VPBs).
Main Methods:
- DFA, power-law slope (beta index), and standard deviation of N-N intervals (SDNN) were applied to R-R interval series.
- Analysis included edited and unedited (with VPBs) Holter data from healthy controls and Chagas patients with varying LV function.
Main Results:
- Long-term fractal dynamics (alpha(2)) were altered in Chagas patients regardless of LV dysfunction.
- Short-term dynamics (alpha(1)) showed reduced complexity in patients with impaired LV function, especially with VPBs.
- The beta index was reduced in Chagas patients, correlating with alpha(2).
Conclusions:
- Altered long-term fractal HR dynamics may signify early autonomic dysfunction in Chagas disease.
- Short-term fractal dynamics reveal more random behavior in patients with LV dysfunction, influenced by ectopy.
- Further research is needed to establish these indices as predictors of mortality.