Effects of mental stress on myocardial perfusion in patients with ischemic heart disease. The purpose of the present study was to determine whether and to what extent mental stress can reproduce the perfusion defects that are known to be induced by exercise. Twenty-four patients with recent myocardial infarction (New York Heart Association functional class I) and evidence of ischemic response were evaluated by means of SESTAMIBI scintigraphy performed once after exercise and then again within 2 days after mental arithmetic. Baseline, exercise, and mental stress planar scintigrams were divided into 15 segments, and each segment was reviewed and scored on a scale of 0 to 3 by experienced observers using circumferential profile analysis. Conflicting scores were resolved by consensus. Electrocardiographic abnormalities were found in 15 of 24 patients during exercise and in none during mental arithmetic. Chest pain was experienced by five patients during exercise and by none during mental stress. Twenty patients showed reversible perfusion defects during mental stress. Of the 360 pooled scintigram segments, 99 evidenced uptake defects during exercise, and 48 of these showed the same defects during mental stress. Twenty of the remaining 51 of 99 segments were adjacent to segments showing reversible hypoperfusion, suggesting milder hypoperfusion in these segments during mental arithmetic than during exercise. Furthermore, 10 segments showed reversible defects only during mental stress such that seven of these occurred in areas adjacent to those that had shown exercise-induced reversible perfusion defects, two occurred in areas that had shown fixed SESTAMIBI defects during exercise, and one occurred in a segment that had shown completely normal uptake during exercise. 