This study examined the relationship between "emotional responsivity" (i.e., individuals who exhibit relatively large variations of self-reported tension levels) and myocardial ischemia. One hundred thirty-six patients with coronary artery disease underwent 48 hr ambulatory electrocardiographic (ECG) monitoring and laboratory mental stress testing using radionuclide angiocardiography. Compared with individuals characterized as low emotional responders, a higher proportion of individuals characterized as high emotional responders exhibited wall motion abnormalities in response to laboratory mental stress testing and were more likely to exhibit ECG ST-segment depression (> or = 1 mm for > or = 1 min) during routine daily activities. These results suggest that emotional responsivity may represent an individual difference characteristic that is associated with an increased likelihood of exhibiting myocardial ischemia in both the laboratory and the real-world setting.