TITLE

Myocardial I-MIBG scintigraphy predicts an impairment in myocardial functional reserve during dobutamine stress in patients with idiopathic dilated cardiomyopathy

AUTHOR(S)
Ohshima, Satoru; Isobe, Satoshi; Hayashi, Daisuke; Abe, Shinji; Kato, Katsuhiko; Murohara, Toyoaki
PUB. DATE
February 2013
SOURCE
European Journal of Nuclear Medicine & Molecular Imaging;Feb2013, Vol. 40 Issue 2, p262
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Purpose: We investigated whether myocardial I-metaiodobenzylguanidine (I-MIBG) scintigraphy predicts impairment of myocardial functional reserve in response to dobutamine stress in patients with idiopathic dilated cardiomyopathy (DCM). Methods: Forty DCM patients (LVEF 39 ± 12 %) underwent myocardial I-MIBG scintigraphy, echocardiography, and cardiac catheterization. Myocardial I-MIBG uptake was quantified as the delayed heart to mediastinum (H/M) ratio and washout rate (WR). Local denervation was evaluated on polar map images. LV d P/d t and T were determined from left ventricular pressure curves at baseline and during dobutamine infusion (15 μg/kg /min). Patients were classified into two groups as follows: group A comprised 21 patients showing a delayed H/M ratio of <1.9 (median value); group B comprised 19 patients showing a delayed H/M ratio of ≥1.9. Results: The percentage change in heart rate (%HR), LV d P/d t (%LV d P/d t), and T (% T) from baseline to dobutamine stress were significantly more reduced in group A than in group B (39.3 ± 20.2 %, 55.2 ± 24.1 %, p < 0.01; 102.3 ± 46.3 %, 152.0 ± 72.3 %, p < 0.05; 38.7 ± 15.3 %, 46.9 ± 15.4 %, p < 0.05, respectively). No significant differences between the two groups were observed in the echocardiographic parameters or baseline cardiac catheterization parameters. Significant correlations were found between delayed H/M ratio and %HR ( r = 0.35, p < 0.05), %LV d P/d t ( r = 0.45, p < 0.05) and % T ( r = 0.34, p < 0.05). Significant inverse correlations were also found between WR and %HR ( r = −0.37, p < 0.05), %LV d P/d t ( r = −0.60, p < 0.0001), and % T ( r = −0.34, p < 0.05). SPECT images revealed enhanced denervation from the inferoposterior to anterior wall in accordance with the advancement of global denervation. Conclusion: Reduced I-MIBG uptake and increased washout were related to impairment in adrenergic myocardial functional reserve in idiopathic DCM.
ACCESSION #
84600944

 

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