Aim. To study postoperative dysfunction of interventricular septum in patients with coronary artery disease and severe left ventricular dysfunction and its influence on revascularization outcomes. Material and methods. 112 patients with multivessel coronary artery disease and left ventricular ejection fraction <35% were surveyed. 81 of them underwent on-pump coronary artery bypass grafting including 28 cases of simultaneous mitral valve repair for mitral insufficiency. Left ventricular perfusion and contractility were analyzed by using of ECG-synchronized perfusion myocardial tomography before surgery, in early (7—14 days) and long-term (3—12 months) postoperative period. Results. Patients were divided into two groups: 1st group (n=63) consisted of patients with viable myocardium of the left ventricular lateral wall (≥70% tracer uptake), II group (n=18) consisted of patients with lateral/inferolateral walls perfusion was significantly lower (<50%; p <0.001). Despite more severe postoperative septal dysfunction in group I, revascularization outcomes were significantly better compared with group II: ejection fraction increased by 4.6±5.3% at early stage and by 7.4±9.0% in long-term postoperative period vs. –2.2±5.7/–1.2±3.9% (p1<0.001; p2=0.029); indexed end-systolic volume decreased by 19.5±12.0/23.0±21.8% vs. 9.3±6.6/2.7±7.1% (p1=0,015; p2=0,048). Conclusion. Lateral left ventricular wall viability should be considered in patients with ischemic cardiomyopathy to predict long-term revascularization outcomes. Improvement of central hemodynamic performance is uncertain if sufficient volume of viable myocardium of the lateral wall/its functional recovery after CABG are absent.