Effects of short-term carvedilol on the cardiac sympathetic activity assessed by 123I-MIBG scintigraphy.
BACKGROUND
Autonomic alterations in heart failure are associated with an increase in morbimortality. Several noninvasive methods have been employed to evaluate the sympathetic function, including the Meta-Iodobenzylguanidine (123I-MIBG) scintigraphy imaging of the heart.


OBJECTIVE
to evaluate the cardiac sympathetic activity through 123I-MIBG scintigraphy, before and after three months of carvedilol therapy in patients with heart failure and left ventricular ejection fraction (LVEF) < 45%.


METHODS
Sixteen patients, aged 56.3 +/- 12.6 years (11 males), with a mean LVEF of 28% +/- 8% and no previous use of beta-blockers were recruited for the study. Images of the heart innervation were acquired with 123I-MIBG, and the serum levels of catecholamines (epinephrine, dopamine and norepinephrine) were measured; the radioisotope ventriculography (RIV) was performed before and after a three-month therapy with carvedilol.


RESULTS
Patients' functional class showed improvement: before the treatment, 50% of the patients were FC II and 50% were FC III. After 3 months, 7 patients were FC I (43.8%) and 9 were FC II (56.2%), (p = 0.0001). The mean LVEF assessed by RIV increased from 29% to 33% (p = 0.017). There was no significant variation in cardiac adrenergic activity assessed by 123I-MIBG (early and late resting images and washout rate). No significant variation was observed regarding the measurement of catecholamines.


CONCLUSIONS
The short-term treatment with carvedilol promoted the clinical and LVEF improvement. However, this was not associated to an improvement in the cardiac adrenergic activity, assessed by 123I-MIBG scintigraphy, as well as the measurement of circulating catecholamines.
Miranda
Sandra Marina Ribeiro de
SM
Universidade Federal Fluminense, Niterói, RJ, Brazil. sandramarina@cardiol.br
Mesquita
Evandro Tinoco
ET
Dohmann
Hans Fernando da Rocha
HF
Azevedo
Jader Cunha
JC
Barbirato
Gustavo Borges
GB
Freire
Fabiano de Lima
Fde L
Ribeiro
Mário Luiz
ML
Nóbrega
Antonio Cláudio Lucas da
AC
Coimbra
Alexandro
A
Mesquita
Cláudio Tinoco
CT
D019797:3-Iodobenzylguanidine; D000320:Adrenergic Fibers / Q000187:drug effects; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D002227:Carbazoles / Q000627:therapeutic use*; D000077261:Carvedilol; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000294:innervation / Q000503:physiopathology; D054143:Heart Failure, Systolic / Q000000981:diagnostic imaging / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011412:Propanolamines / Q000627:therapeutic use*; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013318:Stroke Volume / Q000187:drug effects; D013997:Time Factors; D016896:Treatment Outcome
D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D019275:Radiopharmaceuticals; D000077261:Carvedilol; D019797:3-Iodobenzylguanidine