Aim: This study investigated the value of epicardial mapping immediately before CABG in the differentiation of hibernating from scarred myocardium in correlation to the noninvasive gold standard (18)F-FDG PET.
Methods and results: In 35 patients with CAD, myocardial perfusion ((99m)Tc-Tetrofosmin-SPECT), viability ((18)F-FDG-PET), and function (LVangiography) were assessed before CABG. 102 bipolar epicardial electrograms per patient (n = 3570 electrograms) were recorded simultaneously with a ventricular jacket array. Based on the scintigraphic and LV angiographic data at the site of each electrode with good myocardial contact (n = 1963), segments (n = 492, 14.1 +/- 5.6 per patient; mean +/- SD) were classified into three groups: hibernating (n = 139), scarred (n = 104), and control (n = 249). Regional mean bipolar voltage values were calculated for Receiver Operating Characteristic (ROC) analysis. Mean bipolar voltage was significantly lower in scarred when compared to hibernating myocardium. ROC curve analysis (area under the curve of 0.92 +/- 0.47, mean +/- SE) for mean bipolar voltage to discriminate between hibernating and scarred myocardium revealed a sensitivity of 94% with a specificity of 83% at a cut-off value of 8.75 mV.
Conclusion: Hibernating myocardium can be differentiated correctly from scarred myocardium by direct epicardial mapping. In the future, hibernating myocardium may be detectable by body surface mapping techniques using inverse solutions.