Early detection of silent ischemia after bypass grafting.

Silent ischemia (SI) is one of the predictable factors for crises after coronary artery bypass grafting. During the last six months 31 consecutive patients (range of age fifty-one to seventy-one years) underwent twenty-four-hour electrocardiographic monitoring (Holter) in the second postoperative week under ambulatory hospital conditions (total time 750 hours). The patients were investigated by two-channel ST segment Holter (CM1CM5). The results of the analysis were controlled by two independent observers. Criteria for SI were horizontal or downslope ST depression greater than or equal to 1 mm greater than or equal to 1 minute. Five patients (16%) underwent two to eight SI crises/twenty-four hours (mean 4.3).