Impaired cardiac adrenergic innervation assessed by MIBG imaging as a predictor of treatment response in childhood dilated cardiomyopathy.
OBJECTIVE
To evaluate the prognostic value of metaiodobenzylguanidine (MIBG) imaging in childhood cardiomyopathy.


METHODS
Prospective cohort study.


METHODS
Tertiary referral centre.


METHODS
40 children (21 boys, 19 girls; mean (SD) age, 7.0 (5.6) years) with heart failure resulting from idiopathic dilated cardiomyopathy (n = 23) or various other disorders (n = 17).


METHODS
At the initial examination, cardiac (123)I-MIBG uptake and release, circulating noradrenaline (norepinephrine) concentration, x ray cardiothoracic ratio, and echocardiographic variables were recorded. Cardiac MIBG uptake was obtained by measuring the heart to mediastinum activity ratio on the planar image obtained four hours after MIBG injection. MIBG washout rate was evaluated using relative decrease in cardiac activity measured at 20 minutes and four hours. Patients were treated with angiotensin converting enzyme inhibitors, diuretics, and digitalis, and were followed up for 12 (10) months. Fifteen patients did not respond to medical treatment (12 heart transplants; three deaths), and 25 did respond (improved or stable).


RESULTS
Cardiac MIBG uptake was positively correlated with x ray cardiothoracic index (r = 0.55, p = 0.0008) and echocardiographic left ventricular fractional shortening (r = 0.68, p < 0.0001). Among all the clinical and laboratory variables tested, multivariate discriminant analysis showed that the only independent predictor of an unfavourable outcome was a low MIBG uptake (p < 0.001). Survival curves had a mean threshold value of 1.54 for MIBG uptake.


CONCLUSIONS
Impaired cardiac adrenergic innervation is strongly related to adverse outcome in children with dilated cardiomyopathy, independently of the aetiology. MIBG imaging may help to stratify risk in such patients.
Acar
P
P
Service de Cardiologie Pédiatrique, CHU Necker-Enfants Malades, 149 rue de Sèvres, Paris, France.
Merlet
P
P
Iserin
L
L
Bonnet
D
D
Sidi
D
D
Syrota
A
A
Kachaner
J
J
D019797:3-Iodobenzylguanidine / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D002311:Cardiomyopathy, Dilated / Q000097:blood / Q000000981:diagnostic imaging* / Q000188:drug therapy; D002316:Cardiotonic Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004070:Digitalis / Q000627:therapeutic use; D004232:Diuretics / Q000627:therapeutic use; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000294:innervation*; D006801:Humans; D007223:Infant; D008297:Male; D015999:Multivariate Analysis; D009638:Norepinephrine / Q000097:blood; D008517:Phytotherapy; D010946:Plants, Medicinal; D010947:Plants, Toxic; D011379:Prognosis; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000378:metabolism; D012307:Risk Factors; D015996:Survival Rate; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging*
D000806:Angiotensin-Converting Enzyme Inhibitors; D002316:Cardiotonic Agents; D004232:Diuretics; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D009638:Norepinephrine