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Regional systolic function, myocardial blood flow and glucose uptake at rest in hypertrophic cardiomyopathy
P Perrone-Filardi1, S L Bacharach, V Dilsizian
1Cardiology Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
Insights
In hypertrophic cardiomyopathy (HC), regional differences in 18fluorodeoxyglucose (FDG) uptake, a marker of metabolism, correlate with regional differences in systolic function. This suggests a link between metabolic and functional changes in HC patients.
Area of Science:
- Cardiology
- Nuclear Medicine
- Biomedical Imaging
Background:
- Mildly symptomatic patients with hypertrophic cardiomyopathy (HC) exhibit decreased 18fluorodeoxyglucose (FDG) uptake and blood flow in the ventricular septum compared to the lateral wall.
- The relationship between regional metabolic heterogeneity and heterogeneous regional systolic function in HC remains unclear.
Purpose of the Study:
- To investigate the association between regional metabolic differences and regional systolic function in patients with hypertrophic cardiomyopathy (HC).
- To determine if metabolic heterogeneity in HC is linked to variations in regional systolic performance.
Main Methods:
- Positron emission tomography (PET) with oxygen-15-water and FDG was used to assess regional blood flow and metabolism.
- Nuclear magnetic resonance imaging (MRI) was employed to evaluate regional anatomy and systolic function at rest.
- Ten symptomatic HC patients without coronary artery disease were studied.
Main Results:
- Regional blood flow was similar between the ventricular septum and lateral wall in HC patients.
- FDG uptake was significantly higher in the lateral wall compared to the septum (p < 0.01).
- Regional systolic wall thickening was also significantly greater in the lateral wall than in the septum (p < 0.001).
Conclusions:
- Regional metabolic heterogeneity, indicated by FDG uptake, is associated with heterogeneous regional systolic function in hypertrophic cardiomyopathy (HC).
- The findings suggest that metabolic variations contribute to functional differences within the hypertrophied ventricle.
Abstract:
Decreased 18fluorodeoxyglucose (FDG) uptake and blood flow at rest in the ventricular septum, as compared with the lateral wall, have been reported in mildly symptomatic patients with hypertrophic cardiomyopathy (HC). To assess whether regional metabolic heterogeneity in patients with HC is related to heterogeneous regional systolic function, 10 symptomatic patients (mean age 36 +/- 17 years) with HC and no coronary artery disease underwent positron emission tomography with oxygen-15-water and FDG, and nuclear magnetic resonance imaging at rest to assess regional anatomy and systolic function. Regional absolute blood flow was similar between the ventricular septum and lateral wall. In contrast, FDG activity was significantly greater in the lateral wall than in the septum (1,023 +/- 588 vs 767 +/- 388 nCi/ml, respectively; p < 0.01). However, regional systolic wall thickening was also significantly greater in the lateral wall than in the septum (5.3 +/- 4.3 vs 2.4 +/- 4.0 mm, respectively; p < 0.001). Patients were then divided into group A (n = 5) with similar regional wall thickening in the septum and lateral wall, and group B (n = 5) with greater thickening in the lateral wall than in the septum. In both groups, regional blood flow was similar between the septum and lateral wall. However, the regional septal-to-lateral FDG activity ratio was 0.97 +/- 0.31 in group A, and 0.74 +/- 0.25 in group B (p < 0.01); the ratio in group A did not differ from that in 5 normal subjects (1.02 +/- 0.58).(ABSTRACT TRUNCATED AT 250 WORDS)