Cardiac sympathetic dysfunction contributes to left ventricular remodelling after acute myocardial infarction

To investigate the role of the cardiac sympathetic nervous system in left v entricular remodelling, 50 patients with first-time acute myocardial infarc tion (AMI) and patency of the infarct-related artery after reperfusion unde rwent quantitative iodine-123 metaiodobenzylguanidine (MIBG) imaging at 4 d ays and 4 weeks (n=42), and quantitative technetium-99m tetrofosmin imaging at 2 days after AMI. They also underwent both ventriculography and coronar y angiography on admission and about 4 weeks after AMI. On the basis of lef t ventricular end-systolic volume (LVESV), patients were divided into two g roups. Patients with LVESV dilatation (n=20) had a significantly lower ejec tion fraction (P<0.003) and a significantly higher severity score of Tc-99m -tetrofosmin (P<0.04), and total severity (P<0.01), <Delta> extent (P<0.007 ) and <Delta> severity (P<0.0008) scores of MIBG than patients without LVES V dilatation (n=30). <Delta> severity score of MIBG was directly correlated with change in LVESV at 4 weeks (r=0.63, P<0.0001). Stepwise linear discri minant function analysis showed that <Delta> severity score of MIBG (P<0.00 02) was the only discriminator of LVESV dilatation. Patients with LVESV dil atation had higher regional washout rates in both the infarct and the non-i nfarct zones than patients without such dilatation. Furthermore, no MIBG pa rameters changed significantly between 4 days and 4 weeks after AMI, In rep erfused AMI, <Delta> severity score of MIBG was related to the degree of ve ntricular dilatation and was the only powerful discriminator of ventricular dilatation, These results suggest that cardiac sympathetic nervous abnorma lity might contribute to left ventricular remodelling in reperfused AMI. MI BG imaging may allow identification of reperfused AMI patients at high risk for left ventricular remodelling.