Predictors of mortality in Chagas' disease: The impact of atrial fibrillation and oral transmission on infected population

Assessment of Left Atrial Structure and Function by Echocardiography in Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia with significant morbidity and mortality. Exacerbated by the aging population, the prevalence of AF is gradually increasing. Accurate evaluation of structure and function of left atrium (LA) has important prognostic significance in patients with AF. Echocardiography is the imaging technique of first choice to assess LA structure and function due to its better availability, accessibility and safety over cardiac computed tomography and cardiac magnetic resonance. Therefore, the aim of this review is to summarize the recent research progress of evaluating LA size by three-dimensional echocardiography and LA function by speckle tracking echocardiography (STE) in predicting the occurrence and recurrence of AF and determining the risk of stroke in AF. In addition, we summarized the role of traditional echocardiography in detecting AF patients that are at high risk of heart failure or cardiovascular death.

The entrance route: Oral, mucous, cutaneous, or systemic has a marked influence on the outcome of Trypanosoma cruzi experimental infection

In recent decades, the oral infection of Trypanosoma cruzi has gathered increased attention due to frequent outbreaks that can lead to more severe clinical signs than those usually found in the areas of vector transmission. This study addresses the main routes of infection using metacyclic trypomastigotes (MT) and blood trypomastigotes (BT). Herein, BALB/c mice were infected with the Colombian (TcI) strain via intraperitoneal (IP), oral, intragastric (IG), ocular (OC) and cutaneous (CT) routes with 10⁶ culture-derived MT or BT. Parasitemia was intermittent and low in animals inoculated with MT, in contrast, high parasitemia levels were found in BT-mice. A tropism for the muscles was observed in oral or IG infection with BT. Differently, the parasite was widely distributed in the tissues of mice infected with MT. However, the intensity of the inflammation infiltrating the tissues was higher in oral or IG infection with BT. Animals inoculated with BT via the IG route had similar serum levels of IFN-γ and smaller IL-10 compared to those infected with MT via the IG route. TNF-α levels were higher in the serum from BT-animals, which could explain the higher intensity of heart inflammation in these animals. Our results suggest that the infective form and the route of infection differentially modulated the outcome of Trypanosoma cruzi mice infection.

Left Atrial Structure and Function Predictors of New-Onset Atrial Fibrillation in Patients with Chagas Disease

BACKGROUND

Atrial fibrillation (AF) carries ominous consequences in patients with Chagas disease. The aim of this study was to determine whether left atrial (LA) volume and function assessed using three-dimensional echocardiographic (3DE) imaging and two-dimensional speckle-tracking echocardiographic deformation analysis of strain (ε) could predict new-onset AF in patients with Chagas disease.

METHODS

A total of 392 adult patients with chronic Chagas disease (59% women; mean age, 53 ± 11 years) who underwent echocardiography were consecutively enrolled in this prospective longitudinal study. Echocardiographic evaluation included two-dimensional (2D) Doppler echocardiography, with evaluation of left ventricular systolic and diastolic function, LA size, and LA and left ventricular function on 3DE and ε analyses. Multivariate Cox proportional-hazards regression analysis models adjusting for age, sex, hypertension, presence of a pacemaker, and 2D Doppler echocardiographic parameters were used to test if the variables of interest had independent prognostic value for AF prediction.

RESULTS

Patients with Chagas disease were followed for 5.6 ± 2.7 years. Among these, 139 (35.5%) had the indeterminate form, 224 (57.1%) had the cardiac form, five (1.3%) had the digestive form, and 24 (6.1%) had the cardiodigestive form. The study end point of AF occurred in 45 patients. Total LA emptying fraction (hazard ratio, 0.93; 95% CI, 0.89-0.98; P = .002), passive LA emptying fraction (HR, 0.95; 95% CI, 0.91-0.99; P = .02), and peak negative global LA ε (HR, 1.22; 95% CI, 1.05-1.41; P = .01) were predictors of new-onset AF independent of clinical and 2D Doppler echocardiographic parameters.

CONCLUSIONS

LA function assessed on 3DE and ε analyses predicts new-onset AF in patients with Chagas disease independent of clinical and 2D Doppler echocardiographic indexes.

Clinical outcomes of thirteen patients with acute chagas disease acquired through oral transmission from two urban outbreaks in northeastern Brazil

BACKGROUND

Outbreaks of orally transmitted Trypanosoma cruzi continue to be reported in Brazil and are associated with a high mortality rate, mainly due to myocarditis.

METHODS

This study is a detailed report on the disease progression of acute Chagas disease in 13 patients who were infected during two micro-outbreaks in two northeastern Brazilian towns. Clinical outcomes as well as EKG and ECHO results are described, both before and after benznidazole treatment.

RESULTS

Fever and dyspnea were the most frequent symptoms observed. Other clinical findings included myalgia, periorbital edema, headache and systolic murmur. Two patients died of cardiac failure before receiving benznidazole treatment. EKG and ECHO findings frequently showed a disturbance in ventricular repolarization and pericardial effusion. Ventricular dysfunction (ejection fraction <55%) was present in 27.3% of patients. After treatment, EKG readings normalized in 91.7% of patients. Ventricular repolarization abnormalities persisted in 50% of the patients, while sinus bradycardia was observed in 18%. The systolic ejection fraction normalized in two out of three patients with initially depressed ventricular function, while pericardial effusion disappeared.

CONCLUSIONS

Myocarditis is frequently found and potentially severe in patients with acute Chagas disease. Benznidazole treatment may improve clinical symptoms, as well as EKG and ECHO findings.