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Electrocardiographic abnormalities in Trypanosoma cruzi seropositive and seronegative former blood donors
Antonio L Ribeiro1, Ester C Sabino, Milena S Marcolino
1Hospital das Clínicas and Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Insights
Electrocardiogram (ECG) abnormalities are more common in Trypanosoma cruzi infected blood donors. Specific ECG findings can help identify infected individuals with reduced left ventricular ejection fraction (LVEF) needing follow-up.
Area of Science:
- Cardiology
- Infectious Diseases
- Public Health
Background:
- Blood donor screening frequently identifies new cases of Trypanosoma cruzi infection.
- Most infected donors are asymptomatic with chronic indeterminate Chagas disease.
- Limited data exists on electrocardiogram (ECG) findings in infected blood donors.
Purpose of the Study:
- To determine the prevalence of ECG abnormalities in T. cruzi seropositive versus seronegative blood donors.
- To identify ECG markers associated with left ventricular (LV) dysfunction in infected donors.
Main Methods:
- Retrospective study of 499 T. cruzi seropositive and 483 seronegative blood donors in Brazil.
- All participants underwent clinical evaluation, ECG, and echocardiogram (Echo).
- ECG and Echo data were analyzed blindly; LV dysfunction defined as LV ejection fraction (EF) < 0.50%.
Main Results:
- Right bundle branch block and left anterior fascicular block were more frequent in seropositive donors.
- QRS and QTc durations correlated with reduced LV ejection fraction (LVEF).
- ECG showed 92% sensitivity and 99% negative predictive value for detecting reduced LVEF in seropositive donors.
Conclusions:
- ECG abnormalities are significantly more prevalent in T. cruzi seropositive blood donors.
- Certain ECG findings can aid in identifying seropositive individuals with reduced LVEF requiring clinical attention.
- These findings support the use of ECG for risk stratification in asymptomatic Chagas disease patients.
Background:
Blood donor screening leads to large numbers of new diagnoses of Trypanosoma cruzi infection, with most donors in the asymptomatic chronic indeterminate form. Information on electrocardiogram (ECG) findings in infected blood donors is lacking and may help in counseling and recognizing those with more severe disease.
Objectives:
To assess the frequency of ECG abnormalities in T.cruzi seropositive relative to seronegative blood donors, and to recognize ECG abnormalities associated with left ventricular dysfunction.
Methods:
The study retrospectively enrolled 499 seropositive blood donors in São Paulo and Montes Claros, Brazil, and 483 seronegative control donors matched by site, gender, age, and year of blood donation. All subjects underwent a health clinical evaluation, ECG, and echocardiogram (Echo). ECG and Echo were reviewed blindly by centralized reading centers. Left ventricular (LV) dysfunction was defined as LV ejection fraction (EF)<0.50%.
Results:
Right bundle branch block and left anterior fascicular block, isolated or in association, were more frequently found in seropositive cases (p<0.0001). Both QRS and QTc duration were associated with LVEF values (correlation coefficients -0.159,p<0.0003, and -0.142,p = 0.002) and showed a moderate accuracy in the detection of reduced LVEF (area under the ROC curve: 0.778 and 0.790, both p<0.0001). Several ECG abnormalities were more commonly found in seropositive donors with depressed LVEF, including rhythm disorders (frequent supraventricular ectopic beats, atrial fibrillation or flutter and pacemaker), intraventricular blocks (right bundle branch block and left anterior fascicular block) and ischemic abnormalities (possible old myocardial infarction and major and minor ST abnormalities). ECG was sensitive (92%) for recognition of seropositive donors with depressed LVEF and had a high negative predictive value (99%) for ruling out LV dysfunction.
Conclusions:
ECG abnormalities are more frequent in seropositive than in seronegative blood donors. Several ECG abnormalities may help the recognition of seropositive cases with reduced LVEF who warrant careful follow-up and treatment.
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