Electroencephalogram Changes in Patients Undergoing On-Pump Coronary Artery Bypass Grafting

Abstract

Electroencephalogram (EEG) changes associated with on-pump coronary bypass artery grafting (CABG) for ischemic heart disease (IHD) were studied in 28 right-handed men, 10 of whom had concomitant moderate (30–50%) carotid artery stenosis. EEG studies were performed 3–5 days before and 7–11 days after surgery. The control group consisted of 14 healthy men of similar age. Before surgery, patients with IHD differed from the control group in having less marked asymmetry in the power of biopotentials in the θ2 and θ1 rhythms. The differences seen here demonstrated worse conditions for cognitive processes in patients with IHD. After coronary bypass, all patients with IHD showed increases in the power of biopotentials in the θ1 and θ2 rhythms, most marked in the anterior areas of the cortex of the left hemisphere and in patients with carotid artery stenosis. This effect can be regarded as a sign of ischemic brain damage due to surgery with artificial circulation. The locations of changes in the frontal areas of the cortex of the left hemisphere indicate the high susceptibility of these areas, impairments to whose blood supply determines the pattern of cognitive impairments after coronary bypass.