Abstract 14907: 123I-MIBG Myocardial Scintigraphy Predicts The Impairment In Myocardial Functional Reserve During Dobutamine Stress Test In Patients With Idiopathic Dilated Cardiomyopathy
Background: Little is known about the relationship between myocardial denervation and myocardial functional reserve by beta-adrenergic stimulation in failing heart.
Objective: We investigated whether 123I-MIBG myocardial scintigraphy predicts the impairment of myocardial functional reserve in response to dobutamine stress test in idiopathic dilated cardiomyopathy (IDCM) patients.
Methods: Thirty-nine IDCM patients (LVEF 39±12%) underwent myocardial 123I-MIBG scintigraphy and cardiac catheterization. Myocardial 123I-MIBG uptake were quantified as delayed heart-mediadtinum ratio (H/M) and washout rate (WR), and was evaluated of local denervation with SPECT image. LV-dP/dtmax (index of myocardial contractility) and T1/2 (index of myocardial relaxation) were determined from left ventricular pressure curve during dobutamine infusion (15μ g kg-1 min-1). Patients were classified as follows: group A comprised of 21 patients showing delayed H/M of <1.8; group B comprised 18 patients showing the one of ≥1.8.
Results: Percent change in heart rate (%HR) and LV-dP/dtmax(%LV-dP/dtmax) from baseline to dobutamine stress were significantly reduced in group A than those in group B (41±22% vs 60±21%, p<0.01; 116±60% vs 161±67%, p<0.01, respectively). Significant correlations were found between delayed H/M and %HR (r=0.34, p<0.05), %LV-dP/dtmax (r=0.73, p<0.05) and %T1/2 (r=0.31, p<0.05). Significant correlations were also found between WR and %LV-dP/dtmax (r=0.30, p<0.05). The denervation was limited in the inferoposterior and apical wall in group B, otherwise was extended to the anterior wall in group A. Representative case of each study group are shown in figure.
Conclusions: Reduced 123I-MIBG uptake and increased washout rate were related to impairment in adrenergic myocardial functional reserve.
- © 2011 by American Heart Association, Inc.