Research Assistant Research Institute of the McGill University Health Center Montreal, Quebec, Canada
Background: Chronic Chagas Cardiomyopathy (CCC) is a complication of Chagas disease, a parasitic infection endemic in Latin America. Ventricular aneurysms are observed in approximately 60% of CCC patients and are associated with significant ventricular dysfunction and an increased risk of embolism. Cardiac Magnetic Resonance Feature Tracking (CMR-FT) has shown high sensitivity in detecting early myocardial dysfunction across various cardiomyopathies, even when traditional functional parameters appear preserved. However, the specific role of CMR-FT in the assessment of CCC remains unclear.
METHODS AND RESULTS: We conducted a retrospective analysis of adult patients with Chronic Chagas Cardiomyopathy (CCC) who were referred for cardiac magnetic resonance (CMR) evaluation between 2016 and 2022. All CMR studies were performed using a 1.5T Philips Ingenia scanner. Ventricular volumes and functional parameters were obtained from SSFP cine images, while CMR Feature Tracking (CMR-FT) values were derived from short-axis and long-axis views (2CH, 4CH, and LVOT). Global and segmental strain values (basal, mid, and apical) were calculated and compared with previously published normative CMR-FT data. Patients were stratified into four groups based on Left Ventricular Ejection Fraction (LVEF) and the presence or absence of ventricular aneurysms: (1) LVEF > 40% without aneurysm. (2) LVEF < 40% without aneurysm. (3) LVEF > 40% with aneurysm. (3) LVEF < 40% with aneurysm. Descriptive statistics, ANOVA, T-tests, and logistic regression analyses were performed.
A total of 55 patients with CCC who underwent clinically indicated CMR were included (mean age 64 ± 11 years, 53% women). 35 patients had an LVEF > 40%, and 10 had apical aneurysms. Mean Global Radial Strain (GRS), Global Circumferential Strain (GCS) and Global Longitudinal Strain (GLS) values were 19.8±9.3, -12.78±4.6 and -11.13±4.2, respectively and were all significantly different when compared the healthy reference values (45.1±5.9, -22±3.2 and -19.6±1.1; p-values= < 0.001 ). Across the four CCC subgroups, GLS values were progressively worse across the spectrum of the disease (p < 0.001) (Fig. 1). Independently of the LVEF, comparing apical/mid segments to basal, the highest strain ratios were observed in patients without aneurysms, whereas the lowest ratios were seen in patients with aneurysms (Fig. 2).
Conclusion: In patients with Chronic Chagas Cardiomyopathy (CCC), Cardiac Magnetic Resonance Feature Tracking (CMR-FT) demonstrates the potential to detect subclinical apical dysfunction, even in the absence of visually apparent aneurysms and regardless of ejection fraction.
