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Power-law behavior of heart rate variability in Chagas' disease
- Source :
- The American journal of cardiology. 89(4)
- Publication Year :
- 2002
-
Abstract
- Beta slope is a nonlinear index derived from the power-law analysis of 24-hour heart rate variability (HRV); in healthy subjects, the beta index is typically near -1, suggesting a fractal behavior of HRV. There is scarce data on HRV in Chagas' disease. This transversal study intends to describe power-law and linear HRV patterns in different forms of Chagas' disease. Patients and healthy controls (n = 26) without other diseases were submitted to a standardized protocol, including electrocardiography, echocardiography, and 24-hour Holter monitoring. Patients with Chagas' disease were divided into groups according to their left ventricular (LV) systolic function: normal (group 1, n = 85), segmental abnormalities (group 2, n = 49), and reduced ejection fraction (group 3, n = 26). The temporal series were carefully processed to obtain the HRV indexes and beta slope. Despite the differences in the LV systolic function, the 3 groups were comparable in terms of long-term HRV index values. After adjustment for covariates, short-term HRV index values were consistently reduced in the Chagas' disease groups. The beta-index values were also diminished in Chagas' disease groups (group 1: -1.09 +/- 0.03, group 2: -1.11 +/- 0.06; group 3: -1.14 +/- 0.03; and controls: 0.95 +/- 0.03, p0.001). This breakdown of fractal long-range correlation of RR interval dynamics, a strong predictor of mortality in other cardiomyopathies, may reflect cardiac dysautonomia that may have gone undetected in long-term time-domain analysis. This abnormality may explain the increased risk for arrhythmic sudden death found in Chagas' disease even in the absence of signs of LV dysfunction.
- Subjects :
- Chagas disease
Adult
Male
medicine.medical_specialty
Systolic function
Ventricular Dysfunction, Left
Heart Rate
Internal medicine
Heart rate
medicine
Heart rate variability
Humans
Chagas Disease
Aged
Ejection fraction
medicine.diagnostic_test
business.industry
Healthy subjects
Stroke Volume
Middle Aged
medicine.disease
Fractals
Cardiology
Female
Cardiology and Cardiovascular Medicine
business
Holter monitoring
Electrocardiography
Subjects
Details
- ISSN :
- 00029149
- Volume :
- 89
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- The American journal of cardiology
- Accession number :
- edsair.doi.dedup.....66c62447eb6323a5539e11cdffd208e1