Exercise-induced ventricular arrhythmias and vagal dysfunction in Chagas disease patients with no apparent cardiac involvement

Abstract

Introduction: Exercise-induced ventricular arrhythmia (EIVA) and autonomic imbalance are considered as early markers of heart disease in Chagas disease (ChD) patients. The objective of the present study was to verify the differences in the occurrence of EIVA and autonomic maneuver indexes between healthy individuals and ChD patients with no apparent cardiac involvement. Methods: A total of 75 ChD patients with no apparent cardiac involvement, aged 44.7 (8.5) years, and 38 healthy individuals, aged 44.0 (9.2) years, were evaluated using echocardiography, symptom-limited treadmill exercise testing and autonomic function tests. Results: The occurrence of EIVA was higher in the chagasic group (48%) than in the control group (23.7%) during both the effort and the recovery phases. Frequent ventricular contractions occurred only in the patient group. Additionally, the respiratory sinus arrhythmia index was signifi cantly lower in the chagasic individuals compared with the control group. Conclusions: ChD patients with no apparent cardiac involvement had a higher frequency of EIVA as well as more vagal dysfunction by respiratory sinus arrhythmia. These results suggest that even when asymptomatic, ChD patients possess important arrhythmogenic substrates and subclinical disease.

The Brazilian Society of Cardiology and Brazilian Society of Exercise and Sports Medicine Updated Guidelines for Sports and Exercise Cardiology - 2019

“…158 , 159 Sustained ventricular tachycardia is the main cause of SD, and is associated with LV dysfunction, syncope and non-sustained ventricular tachycardia in Holter monitoring or the exercise testing. 160 , 161 In addition, sinus node dysfunction, atrioventricular and intraventricular conduction disorders are common findings in patients with Chagas disease and may progress to complete atrioventricular block. Few studies have evaluated the risk of SD in Chagas patients during intense exercise, and a lack of symptoms does not exclude the presence of cardiomyopathy, even in high-level athletes.…”

Reduced functional capacity in patients with Chagas disease: a systematic review with meta-analysis

“…The treadmill was used to evaluate VO 2 peak in 6 studies [18][19][20][21][22][23] and the cycle ergometer was used in only 1 paper 12 . The VO 2 peak was directly assessed using gas analysis in 3 articles 12,21,23 and estimated by formulas in 4 studies [18][19][20]22 .…”

“…In fact, patients with Chagas disease without apparent cardiac disease have excellent prognosis, similar to that of healthy individuals. However, although VO 2 peak values are within the normal range, exercise tests in these patients are highly recommended since Chagas patients present a greater number of exercise-induced arrhythmias, both during exercise and the recovery phase 18 .…”

Exercise tests in Chagas cardiomyopathy: an overview of functional evaluation, prognostic significance, and current challenges

“…Additionally, EIVA is a marker of cardiovascular mortality in patients with ChC 20 . As EIVA occurs frequently in ChC patients without apparent cardiac involvement 8 , the conventional maximal exercise test is clinically relevant for risk stratification in this population.…”

“…However, patients with ChC, regardless of systolic function and degree of ventricular dilation, have impaired functional capacity 7 , which reinforces the need for evaluation by exercise tests. Even in asymptomatic patients, non-invasive methods such as conventional maximal exercise test and cardiopulmonary exercise testing (CPET) can detect significant changes, including exerciseinduced ventricular arrhythmias (EIVAs) 8 and chronotropic incompetence 9 . However, the usefulness of exercise tests in ChC has not been systematically discussed.…”