[Symptomatic and silent myocardial ischemia during drug therapy and after aortocoronary bypass].

In 53 patients with stable angina pectoris 24-hour ambulatory electrocardiographic monitoring (Holter) and bicycle ergometry were used before and six months after a coronary bypass. The examination before operation was made while anti-ischaemic medication was administered, the examination after revascularization was done without medication. The patients were divided into group A (31 patients where complete revascularization of the myocardium was made) and group B (22 patients with incomplete revascularization) and the results were compared during medication and after aortocoronary bypass. In patients of group A revascularization prolonged significantly the load period during ergometry, as compared with medication (from 7.2 +/- 2.2 min. to 9.1 +/- 2.4 min., p < 0.01), the depression of the ST segment in lead V5 was reduced (from 1.3 +/- 0.8 mm to 0.8 +/- 1.0 mm, p < 0.05) and the number of painful episodes during Holter monitoring (from 1 +/- 1 to 0, p < 0.01). In patients of group B none these parameters improved. Medicamentous treatment eliminated ischaemia during a load in 16% of patients in group A, while revascularization did so in 61% (p < 0.01). In patients of group B the success rate of medication was 9%, in revascularization 14% (p = n.s.). During Holter monitoring after revascularization no episodes of ST depressions associated with anginous pain were recorded, although the mean number of silent episodes of ST depressions per 24 hours was 6 +/- 8 in patients of group B and 1 +/- 2 in patients of group A. In patients with stable angina pectoris complete revascularization is significantly more effective than anti-ischaemic medication as regards tolerance of loads and suppression of myocardial ischaemia. Silent myocardial ischaemia is frequent after aortocoronary bypasses and its possible occurrence should be taken into account, in particular in patients with incomplete revascularization.