Japanese patients with acute myocardial infarction who present without chest pain.

Previous studies have suggested that patients with acute myocardial infarction (AMI) who presented without chest pain had an unfavorable prognosis due to undertreatment. Despite this, few studies have been conducted on the topic, particularly in Japan. The present analysis aimed at determining whether Japanese AMI patients without chest pain are undertreated and experience higher mortality during hospitalization. Data from the Tokai Acute Myocardial Infarction Study II sample were used, which is a prospective study of all consecutive patients admitted to the 15 acute care hospitals in the Tokai region with the diagnosis of AMI from 2001 to 2003. Data on baseline and procedural characteristics and hospital outcome were collected. Differences in the baseline and procedural characteristics and clinical outcomes between patients presenting with and without chest pain were assessed. We evaluated a total of 1,769 patients who presented with chest pain and 452 who did not. The patients with AMI in the absence of chest pain were older and were more likely to have worse clinical conditions than those with chest pain. They were more likely to be undertreated, although the probability of vasopressor use was higher. The patients without chest pain had a significantly higher in-hospital mortality rate than those with chest pain. According to multivariate analysis, however, chest pain was not identified as an independent predictor of in-hospital death. The results suggest that the higher in-hospital mortality rate among Japanese AMI patients without chest pain could be accounted for by differences in clinical conditions.