Regional myocardial sympathetic denervation precedes the development of left ventricular systolic dysfunction in chronic Chagas' cardiomyopathy.

BACKGROUND

Regional myocardial sympathetic denervation is a conspicuous and early disorder in patients with chronic Chagas' cardiomyopathy (CCC), potentially associated to the progression of myocardial dysfunction

OBJECTIVE

To evaluate in a longitudinal study the association between the presence and the progression of regional myocardial sympathetic denervation with the deterioration of global and segmental left ventricular dysfunction in CCC.

METHODS

18 patients with CCC were submitted at initial evaluation and after 5.5 years to rest myocardial scintigraphy with 123Iodo-metaiodobenzylguanidine and 99mTc-sestamibi and to two-dimensional echocardiography to assess myocardial sympathetic denervation, extent of fibrosis, and the left ventricular ejection fraction (LVEF) and wall motion abnormalities.

RESULTS

In the follow-up evaluation, compared to the initial one, we observed a significant decrease in LVEF (56 ± 11 to 49% ± 12; P = .01) and increased summed defects scores in the myocardial innervation scintigraphy (15 ± 10 to 20 ± 9; P < .01). The presence of regional myocardial sympathetic denervation in ventricular regions of viable non-fibrotic myocardium presented an odds ratio of 4.25 for the development of new wall motion abnormalities (P = .001).

CONCLUSION

Regional and global myocardial sympathetic denervation is a progressive derangement in CCC. In addition, the regional denervation is topographically associated with areas of future development of regional systolic dysfunction in patients with CCC.