Sympathetic Dysautonomia in Heart Failure by 123I-MIBG: comparison between Chagasic, non-Chagasic and heart transplant patients

Abstract

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.

Evaluation of the Autonomic Nervous System in Chronic Chagasic Cardiopathy: A Systematic Review of the Literature

“…The frequency of patients with sympathetic denervation and its extension gradually increased from the indeterminate form, to the cardiac form without LV dysfunction and with LV 5 systolic dysfunction. There was also a correlation between sympathetic denervation and degree of ventricular dysfunction 13 and an association between the degree of sympathetic denervation extension and the previous history of malignant ventricular arrhythmia. 14,16 In patients with chagasic heart disease, a history of sustained ventricular tachycardia correlated with the extent of sympathetic cardiac denervation, but not with the extent of fibrosis, indicating an important role of sympathetic cardiac denervation to trigger ventricular arrhythmia.…”

“…The search for patients in almost all articles was not limited by period in most studies, except in three studies: the study by Landessman et al, 12 in which patients were studied from October 2003 to November 2006; in the study by Souza et al, 11 in which patients were studied between April 2009 and November 2010, and the study by Marino et al 13 , where patients were selected from March 2014 to February 2016. All selected articles included both men and women, with no restrictions on gender.…”

“…Among the methods used for assessment of autonomic denervation of patients with Chagas disease, Marin-Neto et al, 6 submitted the participants to the Valsalva maneuver, tilt test with head elevation and assessment of baroreflex sensitivity through intravenous injection of phenylephrine. Landessman et al, 12 and Marino et al, 13 used myocardial scintigraphy with metaiodobenzylguanidine (MIBG) to verify denervation of autonomic nervous system. Simões et al, 5 Miranda et al, 14 Barizon et al, 15 and Gadioli et al, 16 compared myocardial scintigraphy with MIBG to assess denervation, and myocardial perfusion scintigraphy using the sestamibi technetium (Tc-MIBI).…”

“…6 The studies that used MIBG myocardial scintigraphy had a heterogeneous study population, since one included patients with indeterminate Chagas disease 12 and the other patients with heart failure. 13 The first study suggested the presence of sympathetic denervation in patients with the indeterminate form 12 and the second failed to demonstrate a higher degree of sympathetic denervation in patients with Chagas' disease and heart failure than in patients with heart failure of other etiologies. 13 Four studies used myocardial scintigraphy with MIBG to assess denervation, and MIBI to assess myocardial perfusion.…”

“…13 The first study suggested the presence of sympathetic denervation in patients with the indeterminate form 12 and the second failed to demonstrate a higher degree of sympathetic denervation in patients with Chagas' disease and heart failure than in patients with heart failure of other etiologies. 13 Four studies used myocardial scintigraphy with MIBG to assess denervation, and MIBI to assess myocardial perfusion. The first also included MRI to assess patients with cardiac form of Chagas disease.…”