Relationship of electrocardiographic abnormalities and seropositivity to Trypanosoma cruzi within a rural community in Northeast Brazil

Abstract

The relationship of infection with Trypanosoma cruzi to ECG abnormalities was studied in a defined population in rural Bahia, Brazil. Of 644 individuals 10 years of age or older who had complement fixation tests for antibodies to T. cruzi and ECGs, 53.7% were seropositive. ECG abnormalities were more common in seropositive individuals than in seronegative individuals, and more common in men than in women. The peak prevalence rate of abnormal ECGs occurred among seropositive individuals between 25 and 44 years of age; in this age group ECG abnormalities occurred 9.6 times more frequently among seropositive individuals than among seronegative individuals. The most common abnormalities were ventricular conduction defects, and right bundle branch block with or without fascicular block occurred in 10.7% of the infected population. PR intervals were longer in seropositive individuals than in seronegative individuals. Ventricular extrasystoles were slightly more common in seropositive individuals. A declining prevalence rate of abnormal ECGs among older seropositive individuals suggested selective mortality due to Chagas' heart disease.

Chagas' heart disease

“…Several observational studies mainly conducted in endemic areas in Brazil, Argentina and Venezuela, since the early 1940s disclosed the natural history of Chagas' heart disease 7,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] .…”

“…Thus, no adequate identification of cardiac involvement is usually provided in most of the rural-based studies [27][28][29][30][31][32][33][34][35][36][37] . Conversely, in hospital-based studies the heart disease is usually well characterized, but their results can not be extended to the whole spectrum of the chagasic population 8,[38][39][40][41] .…”

“…Prognosis of chronic Chagas' heart disease -From the studies mentioned above, analyzing prognostic factors of the indeterminate phase in rural populations in which only a superficial evaluation of the heart condition was carried out, it became apparent that the mere appearance of ECG changes entailed a bad prognosis 34,35 . Also, a retrospective analysis of seropositive individuals followed over 18 years revealed that right bundle branch block was three times more common in fatal cases than in survivors 34 .…”

Early electrocardiographic abnormalities in Trypanosoma cruzi-seropositive children.

“…6,7 In cross-sectional observations the prevalence of ECG abnormalities increases with age with a peak at the fourth to fifth decade of life, while the differential risk of ECG abnormalities comparing seropositive with seronegative subjects decreases with age. 8 Cardiopathy seems to occur in family clusters, but no single risk factor has been clearly associated with disease progression at individual or population levels. 4 It is estimated that approximately 20-30% of seropositive subjects will develop heart disease during the course of their lives.…”

Impacto da infecção chagásica sobre algumas características demográficas: resultados de um estudo ecológico

“…Caracteriza-se por ser uma infecção crônica e por estar associada à patologias graves, principalmente do aparelho circulatório. Em estudos de prevalência, em áreas endêmicas, os infectados apresentam 10-20% de excesso de alterações cardíacas (Maguirre et al, 1983;Schenone et al, 1983;Baruffa et al, 1983). Em estudos epidemiológicos longitudinais, os indivíduos infectados apresentam taxas elevadas de problemas cardíacos e mortalidade (Mota et al, 1990;Maguirre et al, 1987;Pereira et al, 1985;Maguirre et al, 1982;Pugliese et al, 1976;.…”