Mental Stress–Induced Ischemia in the Laboratory and Ambulatory Ischemia During Daily Life

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Abstract
Background The purpose of this study was to determine the correspondence of mental stress–induced ischemia in the laboratory with ambulatory ischemia and to assess the relationship between hemodynamic responses to mental stress and the occurrence of ischemia. Although exercise testing is usually used to elicit myocardial ischemia, ischemia during daily life usually occurs at relatively low heart rates and in the absence of strenuous physical exercise. Mental stress has been shown to trigger ischemic events in the laboratory at lower heart rates but at blood pressures comparable to exercise. We therefore compared the extent to which mental stress and exercise testing identify patients who develop ischemia out of hospital. Methods and Results One hundred thirty-two patients with documented coronary disease and recent evidence of exercise-induced myocardial ischemia underwent 48-hour ambulatory monitoring and radionuclide ventriculography during exercise and mental stress testing. Patients who displayed mental stress–induced ischemia in the laboratory were more likely to exhibit ischemia during daily life ( P <.021). Furthermore, patients who exhibited ischemia during ambulatory monitoring displayed larger diastolic blood pressure ( P <.006), heart rate ( P <.039), and rate-pressure product responses ( P <.018) during mental stress. Conclusions Among patients with prior positive exercise stress tests, mental stress–induced ischemia, defined by new wall motion abnormalities, predicts daily ischemia independent of exercise-induced ischemia. Exaggerated hemodynamic responses during mental stress testing also identify individuals who are more likely to exhibit myocardial ischemia during daily life and mental stress.