Usefulness of 500-m walk electrocardiogram test on clinical outcomes in patients with ST-segment elevation myocardial infarction.

The current Japanese guideline for ST-segment elevation myocardial infarction (STEMI) recommends 500-m walk electrocardiogram (ECG) test for patients with STEMI during hospitalization. However, little is known regarding the association between acute phase 500-m walk ECG test and clinical outcomes. The purpose of this study was to investigate the association between 500-m walk ECG test and mid-term clinical outcomes in patients with STEMI. A total of 313 STEMI patients who underwent primary percutaneous coronary interventions were included, and were divided into the successful 500-m group (n = 263) and the unsuccessful 500-m group (n = 50). The primary endpoint was the major adverse cardiovascular events (MACE), which were defined as the composite of all cause death, acute myocardial infarction, readmission for heart failure, and ischemia-driven target vessel revascularization (TVR). During the follow-up period (median 223 days), a total of 55 MACE were observed. The log-rank test revealed that MACE, all cause death, readmission for heart failure, and ischemia-driven TVR were more frequently observed in the unsuccessful 500-m group than the successful 500-m group. In the multivariate Cox proportional hazard model, the unsuccessful 500-m walk ECG test was significantly associated with MACE (OR 5.62, 95% CI 3.08-10.08, P < 0.01) after controlling confounding factors such as age, and serum creatinine levels. In conclusion, the unsuccessful 500-m walk ECG test was significantly associated with poor mid-term outcomes in patients with STEMI. Our results suggest the usefulness of 500-m walk ECG test to stratify the high-risk group from patients with STEMI.