Aims: This study investigated the hypothesis that direct epicardial bipolar mapping is able to predict the recovery of left ventricular (LV) dysfunction in ischaemic myocardium.
Methods and results: In 34 patients with CAD, a maximum of 102 bipolar epicardial electrograms per patient (n=3468 electrograms) were simultaneously recorded with a ventricular jacket array intraoperatively immediately prior to revascularization. Only LV electrograms with good myocardial contact (n=1813, 52+/-14 per patient, mean+/-SD) were analyzed. In accordance to the position of each electrode, segmental myocardial function was assessed by transthoracic echocardiography before and 7+/-2 months (mean+/-SD; range 3-10 months) after CABG using a wall motion score. Preoperatively dysfunctional segments (n=700) were classified as viable (improvement in wall motion score of at least 20% following CABG, n=424) or non-viable (no improvement, n=276). Bipolar voltage was significantly lower in non-viable when compared to viable myocardium (P<0.001, ANOVA) At a cut-off value of 5.9mV, ROC-curve analysis for bipolar voltage (to discriminate between viable and non-viable myocardium) revealed a sensitivity of 83% at a specificity of 83% (area under the ROC-curve of 0.92+/-0.01, mean+/-SE).
Conclusions: Direct epicardial mapping is able to predict the recovery of chronically ischaemic dysfunctional myocardium and thereby proves the presence of myocardial viability.