OBJECTIVES: The purpose of this study was to demonstrate the safety and utility of immediate exercise treadmill testing (IETT) of low risk patients presenting to the emergency department with known coronary artery disease (CAD). BACKGROUND: More than 70% of the two million patients admitted to U.S. hospitals annually for suspected acute myocardial infarction (AMI) are found not to have had a cardiac event. We have previously demonstrated the safety and efficacy of IETT of selected low risk patients without known CAD presenting to the emergency department with chest pain. This study extends this approach to selected patients with a history of CAD. METHODS:: One hundred patients evaluated by the chest pain emergency room to role out AMI underwent IETT using a modified Bruce protocol upon admission to the hospital (median time <1 h). RESULTS:: Twenty-three patients (23%) had positive exercise electrocardiograms (ExECGs); an uncomplicated non-Q wave AMI was diagnosed in two patients. Thirty-eight patients (38%) had negative ExECGs and 39 patients (39%) had nondiagnostic ExECGs. Of these 100 patients, 64 were discharged immediately after IETT, 19 were discharged in less than 24 h after negative serial cardiac enzymes and stable electrocardiograms and 17 were discharged after further evaluation and treatment. There were no complications from exercise testing and no late deaths or AMI during six- month follow-up. CONCLUSIONS:: Immediate exercise treadmill testing of low risk patients with chest pain and known CAD is effective in further stratifying this group into patients who can be safely discharged and those who require hospital admission.
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