Heart Aneurysm in Chagas' Disease

Abstract

Methods Thirteen patients (mean aged 48 ± 3 years, nine male) with chronic Chagas' heart disease, defined as positive serology and epidemiological history, were investigated in a clinical trial designed to analyze the correlation between cardiac sympathetic denervation and myocardial perfusion changes 8. They had normal global systolic ventricular function (LV ejection fraction was 55 ± 2%) and no ventricular dilation, yet showed segmental wall motion abnormalities on MUGA-SPECT. Of these patients, four had apical aneurysm, confirmed by two-dimensional echocardiography and contrast ventriculography during cardiac catheterization. All of them had angiographically normal coronaries. The study was approved by the Institutional Ethics Committee, and all patients signed an informed consent form. Image acquisition and processing-Myocardial perfusion studies were performed at rest after an injection of thallium-201 (148 MBq) and, on the second day, MUGA-SPECT, after in vivo blood-pool labeling with injection of stannous chloride, followed by technetium-99m (740 MBq). Images were acquired using a dual-head digital gamma camera DST-SMV (Sopha Medical Vision-Twinsburg, Ohio, USA) equipped with a low-energy, high-resolution (LEHR) collimator with a 20% energy window centered at 70 KeV for thallium-201 images and at 140 KeV for technetium-99m images. ECG-gated SPECT studies were performed by acquiring 32 projections (60 seconds per projection) over a 180° semicircular orbit with the patient supine. Images were processed on a dedicated computer (Vision PowerStation-IBM-SMV), and tomographic slices were reconstructed and exported in a DICOM 3.0 format to a dedicated workstation with specific software for co-registration calculation. Image co-registration-The free software package VTK CISG Registration ToolKit (vtKCisg) 9 , which relies on registration algorithms based on similarity of voxel cross-correlation, was used. After image alignment, the insertion of the right ventricular myocardium into the interventricular septum was used as an anatomical landmark to check alignment accuracy. Whenever necessary, manual corrections were performed to improve alignment.

Echocardiography in Chagas Heart Disease

“…3,4,14,16 A pioneering necropsy work 17 pointed out the high rate of LV chagasic apical aneurysm found in these patients. This result was confirmed by others studies, 14,18 including a large series of 1078 autopsies 19 in which apical aneurysms were found in Ն half of cases, more frequently in male than in female patients, and at similar proportions in all age groups. Eighty-two percent were found at the LV apex, 9% at the right ventricular (RV) apex, and 9% at both.…”

Pathogenesis of chronic Chagas cardiomyopathy: the role of coronary microvascular derangements

“…Coalescent microinfarctions have also been implicated in the genesis of the typical Chagas disease-related ventricular aneurysms that are postulated to occur in watershed coronary areas 15 . Further necropsy studies in humans correlated the presence of an apical aneurysm with scores proportional to the myocardial mass and coronary perfusion and concluded that ischemic factors could be involved in the genesis of the peculiar lesion of Chagas cardiomyopathy 16 . Following the demonstration that isoproterenol infusion in experimental animals without T. cruzi infection led to the formation of ventricular aneurysms similar to those found in Chagas disease, the neurogenic theory of chronic Chagas disease posited an abnormality in the autonomic control of the coronary circulation that would lead to overactivity of the sympathetic system, causing chronic myocardial ischemia 17 .…”

Prevalência de aneurismas do ventrículo esquerdo em pacientes chagásicos crônicos de duas áreas do Estado do Piauí

“…Até o momento, não há explicação definida para gênese do aneurisma apical. No campo das hipóteses, atribui-se a participação de múltiplos fatores, entre os quais o comprometimento do sistema de condução, produzindo retardo na ativação da área da ponta do coração, resultando em elevada distensão regional que evoluiria para a formação do aneurisma 6 e a indicação de uma fase vascular interveniente na patogênese do aneurisma apical 27 .…”