Silent myocardial ischaemia due to mental stress.

Patients with angina and coronary disease have many episodes of symptomless transient myocardial ischaemia, most of which cannot be explained by physical exertion. 16 patients with typical stable angina pectoris were examined to test the hypothesis that these episodes can be triggered off by ordinary daily events, such as changes in mental activity. Regional myocardial perfusion and ischaemia were assessed by measurement of the uptake of rubidium-82 with positron tomography after mental arithmetic and physical exercise. With mental arithmetic, 12 (75%) patients had abnormalities of regional perfusion, accompanied in only 6 by ST-segment depression and in 4 of these 6 by angina, leaving 6 patients with perfusion abnormalities but neither pain nor electrocardiographic changes. After exercise, all the patients showed abnormal regional myocardial perfusion in the segments that became ischaemic with mental arithmetic. This was accompanied by ST depression in all and angina in 15. The association between mental activity and myocardial ischaemia may operate frequently during everyday life and may explain many of the transient and symptomless electrocardiographic changes in patients with coronary disease.