Abnormalities in Fractal Heart Rate Dynamics in Chagas Disease

Abstract

The long-term fractal HR dynamics altered in chagasic patients with and without LV dysfunction could be an early sign of autonomic dysfunction. Patients with impaired LV function show marked alterations in short-term fractal HR dynamics toward more random behavior, mainly due to frequent ectopy. Prospective studies are necessary to define the value of these indices as predictors of death in Chagas disease.

T-Wave Amplitude Variability and the Risk of Death in Chagas Disease

“…Patients underwent Doppler echocardiography with color flow in an ATL Philips HDI 5000 machine (Philips, Bothell, WA, USA) operated by an experienced ecocardiographer blind to patient clinical status as described elsewhere 16 . The left ventricular ejection fraction (LVEF) obtained by Simpson's method using the equipment software was considered abnormal if inferior to 0.50, according to previous studies on the same sample 17,18 . Left ventricular end‐diastolic dimension and presence of apical aneurysm, evaluated by 2‐dimensional study, were also recorded.…”

Fractal scaling properties of heart rate dynamics following resistance exercise training

“…In some pathologies loss of short-term fractal dynamics manifests as uncorrelated randomness in HR variability. This can be seen in congestive heart failure (22), Chagas disease (1,2), preceding the onset of atrial fibrillation/ventricular tachycardia (19,35,36), and following acute myocardial infarction (26). Loss of fractal dynamics may also be associated with excessive order (pathological periodicity whereby the HR signal is mode locked into a single or very few dominant attractors) as is seen with aging and stable angina pectoris (10,20,27).…”

The Relationship between Heart Rate Variability and Serum Cytokines in Chronic Chagasic Patients with Persistent Parasitemia

“…The IChD and ChHD groups presented positive blood culture and PCR for T. cruzi . In the Chagas disease group, the median age was 49 years old, 25–60 which was the same as the control group, where the median age was also 49 years old 24–60 . In both the infected and control groups, predominance of women was verified, 17 (58.6%) and 18 (62.1%), respectively.…”

“…Alterations in the vagal subunit have been identified early in Chagas disease in individuals with and without cardiomyopathy, showing abnormal responses in autonomous tests under stimuli, such as the Valsalva maneuver, the sinus arrhythmia test, and orthostatic stress, revealing diminished HRV indices. These indices were evaluated using temporal, spectral, nonlinear, and turbulent heart methods and have been used as markers of cardiac risk in several other diseases 25–27, 30, 32–34, 36 , 55–57 . However, in Chagas disease, no consensus has been achieved regarding their use.…”