BackgroundHeart failure (HF) is a severe public health problem because of its high
morbidity and mortality and elevated costs, thus requiring better
understanding of its course. In its complex and multifactorial pathogenesis,
sympathetic hyperactivity plays a relevant role. Considering that
sympathetic dysfunction is already present in the initial phases of chronic
Chagas cardiomyopathy (CCC) and frequently associated with a worse
prognosis, we assumed it could be more severe in CCC than in
cardiomyopathies of other etiologies (non-CCC).ObjectivesTo assess the cardiac sympathetic dysfunction 123I-MIBG) of HF,
comparing individuals with CCC to those with non-CCC, using heart transplant
(HT) patients as denervated heart parameters.MethodsWe assessed 76 patients with functional class II-VI HF, being 25 CCC (17
men), 25 non-CCC (14 men) and 26 HT (20 men), by use of cardiac
123I-metaiodobenzylguanidine 123I-MIBG)
scintigraphy, estimating the early and late heart-to-mediastinum ratio (HMR)
of 123I-MIBG uptake and cardiac washout (WO%). The 5%
significance level was adopted in the statistical analysis.ResultsThe early and late HMR values were 1.73 ± 0.24 and 1.58 ± 0.27,
respectively, in CCC, and 1.62 ± 0.21 and 1.44 ± 0.16 in
non-CCC (p = NS), being, however, higher in HT patients (p < 0.001). The
WO% values were 41.65 ± 21.4 (CCC), 47.37 ± 14.19% (non-CCC)
and 43.29 ± 23.02 (HT), p = 0.057. The late HMR values showed a
positive weak correlation with left ventricular ejection fraction (LVEF) in
CCC and non-CCC (r = 0.42 and p = 0.045; and r = 0.49 and p = 0.015,
respectively).ConclusionSympathetic hyperactivity 123I-MIBG) was evidenced in patients
with class II-IV HF, LVEF < 45%, independently of the HF etiology, as
compared to HT patients.
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