Abstract
Chagas disease (CD) will account for 200,000 cardiovascular deaths worldwide over the next 5 years. Early detection of chronic Chagas cardiomyopathy (CCC) is a challenge. We aimed to test if speckle-tracking echocardiography (STE) can detect incipient myocardial damage in CD. METHODS: Among 325 individuals with positive serological tests, 25 (age 55±12yrs) were selected to compose the group with indeterminate form of Chagas disease (IFCD), based on stringent criteria of being asymptomatic and with normal EKG/X-ray studies. This group was compared with a group of 20 patients with CCC (55±11yrs) and a group of 20 non-infected matched control (NC) subjects (48±10yrs). CD patients and NC were submitted to STE and CD patients were submitted to cardiac magnetic resonance (CMR) with late gadolinium administration to detect cardiac fibrosis by the late enhancement technique. Global longitudinal strain (GLS), circumferential (GCS) and radial strain (GRS) were defined as the average of segments measured from three apical view (GLS) and short axis views (GRS and GCS). Regional left ventricular (LV) longitudinal strain (Reg LS) was measured from each of the 17 segments. Twist was measured as systolic peak difference between basal and apical rotation and indexed to LV length to express torsion. RESULTS: STE global indices (GLS, GCS, twist and torsion) were reduced in CCC vs NC (GLS: -14±6.3% vs -19.3±1.6%, p = 0.001; GCS: -13.6±5.2% vs -17.3 ±2.8%; p = 0.008; twist: 8±7° vs 14±7°, p = 0.01 and torsion: 0.96±1°/cm vs 1.9±1°/cm, p = 0.005), but showed no differences in IFCD vs NC. RegLS was reduced in IFCD vs NC in four LV segments: basal-inferior (-16.3±3.3% vs -18.6±2.2%, p = 0.013), basal inferoseptal (-13.1±3.4 vs -15.2±2.7, p = 0.019), mid-inferoseptal (-17.7±3.2 vs -19.4±2, p = 0.032) and mid-inferolateral (-15.2±3.5 vs -17.8±2.8, p = 0.014). These abnormalities in RegLS occurred in the absence of myocardial fibrosis detectable with CMR in nearly 92% of subjects with IFCD, while myocardial fibrosis was present in 65% with CCC. CONCLUSION: RegLS detects early regional impairment of myocardial strain that is independent from fibrosis in IFCD subjects.
Highlights
More than one century after its discovery in 1909 [1] Chagas disease (CD), caused by infection with the Trypanosoma cruzi protozoan, is still a major public health problem in Latin America [2] and, due to migratory moves during the last decades, in non-endemic areas, such as the United States and some European countries [3,4,5].An estimated 50–60% of subjects chronically infected with the T. cruzi remain throughout life with the indeterminate form of CD (IFCD) i.e. they do not show any clinical signs of organic involvement
The aims of this study were (1) to compare left ventricular (LV) systolic global (longitudinal (GLS), radial (GRS) or circumferential (GCS)) and regional LV longitudinal strain (RegLS) values between individuals with IFCD, age matched non-infected matched control (NC) and patients with the chronic Chagas cardiomyopathy (CCC); and (2) to observe if LV strain abnormality correlates with presence and the extent of myocardial fibrosis measured by cardiac magnetic resonance imaging (CMR)
This study shows that LV twist and torsion values are reduced only in advanced forms of CD, while previous data reported in a small subset of 9 patients with IFCD by Garcıa-Alvarez et al found reduction in twist values compared to controls [22]
Summary
More than one century after its discovery in 1909 [1] Chagas disease (CD), caused by infection with the Trypanosoma cruzi protozoan, is still a major public health problem in Latin America [2] and, due to migratory moves during the last decades, in non-endemic areas, such as the United States and some European countries [3,4,5].An estimated 50–60% of subjects chronically infected with the T. cruzi remain throughout life with the indeterminate form of CD (IFCD) i.e. they do not show any clinical signs of organic involvement. The concept of the IFCD has been occasionally challenged [6], its definition—as applied to the condition of an infected individual who is asymptomatic and without abnormalities in the physical exam, the 12-lead electrocardiography (EKG) and the radiological examination of the heart, esophagus and colon—is time honored and maintained in recent guidelines [7, 8] This is mainly due to the belief that as long as the infected individual remains with this indeterminate form of the disease, the prognosis is good, and the risk of death is similar to that of non-infected matched control (NC) subjects. The second is whether any anatomical or functional abnormality detected in individuals with the IFCD would herald the subsequent development of CCC in the natural history of the disease [14]
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