A 58-year-old woman with a history of myocardial infarction 6 months ago, currently on dual antiplatelet therapy and a beta-blocker, presents for elective total abdominal hysterectomy. She reports dyspnea on climbing one flight of stairs and has an ejection fraction of 40% on recent echocardiography. Her resting heart rate is 68 bpm, blood pressure 128/82 mmHg, and oxygen saturation 96% on room air. What is the most appropriate next step in her pre-anesthetic evaluation?