Mental Stress Provokes Ischemia in Coronary Artery Disease Subjects Without Exercise- or Adenosine-Induced Ischemia

ObjectivesThe purpose of this study was to investigate the possibility that some patients with coronary artery disease (CAD) but negative exercise or chemical stress test results might have mental stress-induced ischemia. The study population consisted solely of those with negative test results.BackgroundMental stress-induced ischemia has been reported in 20% to 70% of CAD subjects with exercise-induced ischemia. Because mechanisms of exercise and mental stress-induced ischemia may differ, we studied whether mental stress would produce ischemia in a proportion of subjects with CAD who have no inducible ischemia with exercise or pharmacologic tests.MethodsTwenty-one subjects (14 men, 7 women) with a mean age of 67 years and with a documented history of CAD were studied. All subjects had a recent negative nuclear stress test result (exercise or chemical). Subjects completed a speaking task involving role playing a difficult interpersonal situation. A total of 30 mCi 99mTc-sestamibi was injected at one minute into the speech, and imaging was started 40 min later. A resting image obtained within one week was compared with the stress image. Images were analyzed for number and severity of perfusion defects. The summed difference score based on the difference between summed stress and rest scores was calculated. Severity was assessed using a semiquantitative scoring method from zero to four.ResultsSix of 21 (29%) subjects demonstrated reversible ischemia (summed difference score ≥3) with mental stress. No subject had chest pain or electrocardiographic changes during the stressor. Mean systolic and diastolic blood pressure and heart rate all increased between resting and times of peak stress.ConclusionsMental stress may produce ischemia in some subjects with CAD and negative exercise or chemical nuclear stress test results

Dobutamine pharmacodynamics during dobutamine stress echocardiography and the impact of β-blocker withdrawal: A report from the women\u27s ischemic syndrome evaluation study

Study Objectives. To determine the pharmacodynamic parameters of dobutamine during dobutamine stress echocardiography (DSE) and to determine how β-blocker withdrawal the evening before DSE affects responses to dobutamine during DSE. Design. Retrospective analysis. Setting. University medical center. Patients. One hundred thirty-six women who had chest pain or other symptoms suggestive of myocardial ischemia and were considered to have a clinical indication for coronary angiography. Measurements and Main Results. Patients underwent DSE with dobutamine dosages titrated from 5 to 40 pg/kg/minute. The infusion was terminated if the patient reached target heart rate or symptoms developed. Those taking β-blockers withheld their doses the evening before DSE. Traditional pharmacodynamic modeling revealed a wide range in responses to dobutamine. Data for 62% of patients not taking β-blockers were described by the Emax (maximum heart rate response to dobutamine) model, whereas data for only 39% of patients taking β-blockers were best described by this model (p=0.01). Patients taking β-blockers also had a smaller mean increment in left ventricular ejection fraction (10.8% ± 4.2% vs 14.1% ± 9.3%, p\u3c0.01), a trend toward a higher ED50 (dobutamine dosage rate causing half the maximum heart-rate response; median 16.8 pg/kg/min, p=0.12) and a lower sigmoidicity factor determining the shape of the curve (median 2.1, p=0.03). Conclusion. The response to dobutamine exhibits wide interpatient variability, even in the absence of β-blockade. Nonetheless, in the absence of β-blockers, in most patients the dobutamine response reaches a plateau by the time the maximum infusion rate (40 pg/kg/min) is reached. Withdrawal of β-blockers the evening before DSE may be inadequate time for elimination of β-blocker effect, requiring the addition of atropine to achieve the desired response during DSE