Author + information
- Received November 18, 1992
- Revision received June 21, 1993
- Accepted July 1, 1993
- Published online December 1, 1993.
- Avanindra Jain, MD, FACC∗,
- G.Hunter Myers, MD, FACC,
- Peter M. Sapin, MD, FACC and
- Robert A. O'Rourke, MD, FACC
- ↵∗Address for correspondence: Dr. Avanindra Jain, Division of Cardiology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, Texas 78284.
Objectives. This study was conducted to determine the diagostic yield and risks of a symptom limited treadmill exercise test before hospital discharge.
Background. Currently, predischarge low level and 6-week symptom-limited exercise treadmill tests are recommended for risk stratification after myocardial infarction. However, few data exist on the safety and value of a predischarge symptom-limited exercise test.
Methods. We utilized a modified Bruce protocol starting at 1.7 mph and 0 grade with 3-min stage in 150 consecutive patients 6.4 ± 3.1 days after myocardial infraction. Each exercise test was interpreted for duration, symptom and ST segment changes at the low level (70% of predicted heart rate) and symptom-limited end point.
Results. There were no complications related to the symptom-limited exercise test. The test results were positive in only 23% of the patients at the low level end point, but were positive in 40% of the patients at the later symptom-limited end point (p < 0.001). During a mean follow-up period of 15 ± 5 months in 138 patients (92%), 50 patients (36%) had a cardiac event. Of the patients with a cardiac event, significantly more (p < 0.001) had a positive exercise test at the symptom-limited end point (31 vs. 16 patients). Five patients with a negative and 14 patients with a nondiagnostic symptom-limited exercise test had an event.
Conclusion. In patients with uncomplicated myocardial infarction, we demonstrated the safety of an early symptom-limited treadmill exercise test. Symptom-limited exercise tests will identify more patients with inducible ischemia who are at risk of future cardiac events and who may benefit from early intervention.
- Received November 18, 1992.
- Revision received June 21, 1993.
- Accepted July 1, 1993.