Cardiac sympathetic activity is associated with inflammation and neurohumoral activation in patients with idiopathic dilated cardiomyopathy.
BACKGROUND
Idiopathic dilated cardiomyopathy (IDC) is characterized by sympathetic nervous overactivity, inflammation and neurohumoral activation; however, their interrelationships are poorly understood.


RESULTS
We studied 99 patients with IDC (age 54 +/- 1 years, left ventricular ejection fraction (EF) 40 +/- 1%, maximum oxygen uptake (VO(2)max) 20 +/- 1 ml kg(-1) min(-2), mean +/- SEM) by using (123)I-metaiodobenzylguanidine (MIBG) imaging. MIBG washout and MIBG heart/mediastinum (H/M)-ratio at 4 h postinjection were calculated. In addition, the plasma levels of interleukin (IL)-6 and N-terminal B-type natriuretic peptide (NT-proBNP) were measured. MIBG washout and MIBG H/M ratio had a significant correlation with IL-6 (r = 0.42, P<0.001 and r = -0.31, P<0.01) and NT-proBNP (r = 0.48, P<0.001 and r = -0.40, P<0.001). During a median follow-up of 4.1 years, 20 patients (20%) had an adverse cardiac event (death, heart transplantation or application of biventricular pacemaker or implantable cardioverter-defibrillator). In these patients, MIBG washout was higher (53 +/- 4 versus 40 +/- 2%, P = 0.01) and H/M ratio lower (1.38 +/- 0.04 versus 1.51 +/- 0.02, P = 0.01) than in patients without an event.


CONCLUSIONS
In dilated cardiomyopathy, myocardial sympathetic innervation and activity are related to inflammation and neurohumoral activation. These relationships are at least partly independent of left ventricular function and exercise capacity.
Turpeinen
Anu K
AK
Department of Medicine, Kuopio University Hospital and University of Kuopio, Kuopio, Finland. anu.turpeinen@kuh.fi
Vanninen
Esko
E
Magga
Jarkko
J
Tuomainen
Petri
P
Kuusisto
Johanna
J
Sipola
Petri
P
Punnonen
Kari
K
Vuolteenaho
Olli
O
Peuhkurinen
Keijo
K
D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009205:Myocarditis / Q000150:complications / Q000503:physiopathology*; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D018377:Neurotransmitter Agents / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000503:physiopathology*
D015850:Interleukin-6; D018377:Neurotransmitter Agents; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain