Clinical significance of denervated but viable myocardium in patients withrecanalized acute myocardial infarction

In patients with acute myocardial infarction (MI), myocardial sympathetic i nnervation evaluated by I-123- metaiodobenzylguanidine myocardial scintigra phy is more sensitive to ischaemia than the associated perfusion abnormalit y of Tl-201 myocardial scintigraphy. The purpose of this study was to evalu ate the scintigraphic indices related to the recovery of left ventricular f unction after acute MI. I-123-metaiodobenzylguanidine and Tl-201-chloride i maging were performed in 15 patients (mean age 60 years, 13 men and 2 women ) 2 weeks after the onset of acute MI. Using a 20-segment visual interpreta tion of the Tl-201 image, myocardial segments were classified into persiste nt defect, redistribution or reverse redistribution, and normal Tl-201 upta ke. The extent of denervated segments showed a fair correlation with the ej ection fraction on admission (r = -0.53, P = 0.04), whereas the extent of p ersistent defect had a close correlation with the ejection fraction at 4 mo nths (r = -0.79, P = 0.01). There was a good correlation between the extent of denervated but viable myocardium and the change in ejection fraction fr om admission to 4 months (r = 0.68, P = 0.01). Thus, denervated but viable myocardium is a scintigraphic index related to the functional recovery of l eft ventricular pump function after acute MI. ((C) 1999 Lippincott Williams & Wilkins).