# Serum Cytokine Levels and Heart Rate Variability in the Frequency Domain in Patients With Chronic Chagas Heart Disease

## TL;DR

This study examines the relationship between serum cytokine levels and heart rate variability in patients with chronic Chagas heart disease.

## Contribution

The study identifies a novel negative correlation between IL-23 and HRV indices in CCHD patients.

## Key findings

- Serum cytokine levels were higher in CCHD patients compared to controls.
- A negative correlation was found between IL-23 and HRV high-frequency component indices.
- No significant correlations were observed between other cytokines and HRV indices.

## Abstract

The serum cytokine profile is well established in patients with chronic Chagas heart disease (CCHD). Little is known, however, about the relationship between plasma cytokine levels and frequency-domain parameters of heart rate variability (HRV) in patients with CCHD. We included patients with CCHD with ECG and/or echocardiographic abnormalities; people with no cardiac history matched by sex and age served as controls. ELISA performed cytokine quantification. The HRV in the frequency domain was used to detect parasympathetic and sympathetic dysfunction. Serum cytokine levels were higher in patients with CCHD than in controls. No correlation was found between TNF-α, IFN-γ, IL-1β, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-8, IL-2, IL-7, TGF-β, IL-17, and HRV indices. However, a negative correlation between serum IL-23 levels and HRV indices in the high-frequency component was observed (p = 0.044; rho = -0.587). Whether IL-23 may play a role in the pathogenesis of CHCD remains to be determined.