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Relationship between fibrosis and ventricular arrhythmias in Chagas heart disease without ventricular dysfunction
Eduardo Marinho Tassi1, Marcelo Abramoff Continentino2, Emília Matos do Nascimento1
1Instituto de Cardiologia Edson Saad, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil.
Insights
Cardiac fibrosis detected by cardiac magnetic resonance (CMR) predicts ventricular arrhythmia in Chagas disease patients, even with preserved ejection fraction. Fibrosis quantification is key for assessing electrical instability risk.
Area of Science:
- Cardiology
- Medical Imaging
- Electrophysiology
Background:
- Chagas disease patients with segmental wall motion abnormality (SWMA) exhibit poorer prognosis, irrespective of left ventricular ejection fraction (LVEF).
- Cardiac magnetic resonance (CMR) is the gold standard for detecting SWMA and assessing cardiac fibrosis.
Purpose of the Study:
- To quantify cardiac fibrosis using late gadolinium enhancement CMR in Chagas disease patients with preserved or minimally impaired LVEF (>45%).
- To investigate the relationship between fibrosis, SWMA, LVEF, and ventricular arrhythmia in this patient cohort.
Main Methods:
- Sixty-one patients underwent electrocardiogram, treadmill exercise test, Holter monitoring, and CMR.
- Patients were categorized into three groups based on electrocardiogram and CMR findings, including the presence or absence of SWMA.
Main Results:
- Ventricular arrhythmia occurred in 31.1% of patients. Higher fibrosis percentages were observed in patients with ventricular arrhythmia (11.03%) compared to those without (3.01%).
- Fibrosis mass, with a cutoff of 11.78%, was the sole significant predictor of ventricular arrhythmia (p < 0.001), independent of SWMA, LVEF, and other clinical variables.
Conclusions:
- Electrical instability, indicated by ventricular arrhythmia, can manifest in Chagas disease patients even with preserved ventricular function.
- Cardiac fibrosis is the most critical factor associated with ventricular arrhythmia, with its extent correlating with disease complexity.
Background:
Patients with Chagas disease and segmental wall motion abnormality (SWMA) have worse prognosis independent of left ventricular ejection fraction (LVEF). Cardiac magnetic resonance (CMR) is currently the best method to detect SWMA and to assess fibrosis.
Objective:
To quantify fibrosis by using late gadolinium enhancement CMR in patients with Chagas disease and preserved or minimally impaired ventricular function (> 45%), and to detect patterns of dependence between fibrosis, SWMA and LVEF in the presence of ventricular arrhythmia.
Methods:
Electrocardiogram, treadmill exercise test, Holter and CMR were carried out in 61 patients, who were divided into three groups as follows: (1) normal electrocardiogram and CMR without SWMA; (2) abnormal electrocardiogram and CMR without SWMA; (3) CMR with SWMA independently of electrocardiogram.
Results:
The number of patients with ventricular arrhythmia in relation to the total of patients, the percentage of fibrosis, and the LVEF were, respectively: Group 1, 4/26, 0.74% and 74.34%; Group 2, 4/16, 3.96% and 68.5%; and Group 3, 11/19, 14.07% and 55.59%. Ventricular arrhythmia was found in 31.1% of the patients. Those with and without ventricular arrhythmia had mean LVEF of 59.87% and 70.18%, respectively, and fibrosis percentage of 11.03% and 3.01%, respectively. Of the variables SWMA, groups, age, LVEF and fibrosis, only the latter was significant for the presence of ventricular arrhythmia, with a cutoff point of 11.78% for fibrosis mass (p < 0.001).
Conclusion:
Even in patients with Chagas disease and preserved or minimally impaired ventricular function, electrical instability can be present. Regarding the presence of ventricular arrhythmia, fibrosis is the most important variable, its amount being proportional to the complexity of the groups.
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