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Erschienen in:
01.09.2014 | Short Communication
Regional heterogeneity in cardiac sympathetic innervation in acute myocardial infarction: relationship with myocardial oedema on magnetic resonance
Erschienen in: European Journal of Nuclear Medicine and Molecular Imaging | Ausgabe 9/2014
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Purpose
To assess the relationships between myocardial structure and function on cardiac magnetic resonance (CMR) imaging and sympathetic tone on 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy early after myocardial infarction (MI).
Methods
Ten patients underwent 123I-MIBG and 99mTc-tetrofosmin rest cadmium zinc telluride scintigraphy 4 ± 1 days after MI. The segmental left ventricular (LV) relative radiotracer uptake of both 99mTc-tetrofosmin and early 123I-MIBG was calculated. The day after scintigraphy, on CMR imaging, the extent of ischaemia-related oedema and of myocardial fibrosis (late gadolinium enhancement, LGE) was assessed. Accordingly, the extent of oedema and LGE was evaluated for each segment and segmental wall thickening determined. Based on LGE distribution, LV segments were categorized as "infarcted" (56 segments), "adjacent" (66 segments) or "remote" (48 segments).
Results
Infarcted segments showed a more depressed systolic wall thickening and greater extent of oedema than adjacent segments (p < 0.001) and remote segments (p < 0.001). Interestingly, while uptake of 99mTc-tetrofosmin was significantly depressed only in infarcted segments (p < 0.001 vs. both adjacent and remote segments), uptake of 123I-MIBG was impaired not only in infarcted segments (p < 0.001 vs. remote) but also in adjacent segments (p = 0.024 vs. remote segments). At the regional level, after correction for 99mTc-tetrofosmin and LGE distribution, segmental 123I-MIBG uptake (p < 0.001) remained an independent predictor of ischaemia-related oedema.
Conclusion
After acute MI the regional impairment of sympathetic tone extends beyond the area of altered myocardial perfusion and is associated with myocardial oedema.