Exercise-Induced ST Depression in a Diabetic
A 65-year-old woman with type 2 diabetes and a history of atypical chest pain undergoes a exercise stress test. At peak exercise (8 METs), her heart rate is 150 bpm, blood pressure is 170/80 mmHg. The ECG shows 2 mm horizontal ST-segment depression in leads V4-V6 that persists 5 minutes into recovery. She denies chest pain but reports mild shortness of breath. The technician must interpret the significance of these findings and determine the next steps.
1. What is the likely significance of the ST-segment depression in this patient?
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The 2 mm horizontal ST-segment depression in leads V4-V6 is indicative of subendocardial ischemia, likely due to coronary artery disease. In a diabetic patient, atypical symptoms and silent ischemia are common, so the absence of chest pain does not rule out significant ischemia. The persistence of ST depression into recovery further supports ischemia. The technician should recognize this as a positive stress test and promptly report it to the supervising physician, who may recommend further evaluation such as coronary angiography or medical therapy.
2. What immediate actions should the technician take during recovery?
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The technician should continue monitoring the patient closely, keeping her supine or in a comfortable position, and monitor vital signs and ECG until ST changes resolve. Administer oxygen if hypoxemia is present, and have nitroglycerin available if prescribed. Document the time course of ST changes and symptoms. Notify the physician immediately. If the patient develops chest pain or further ECG changes, activate emergency protocols. The technician should also ensure the patient does not ambulate until stable.