The present study identified factors that distinguish early responders (i.e., requested medical assistance < 60 minutes after the onset of acute myocardial infarction [AMI] symptoms) from late responders (i.e., request made > or = 60 minutes after symptom onset). A questionnaire developed to assess demographic characteristics, contextual factors, antecedents to symptom onset, and behavioral, affective, and cognitive responses was administered in the hospital to 501 patients with documented AMI. Patients who believed that their symptoms were cardiac in nature were more likely to be early responders, whereas patients who attributed their symptoms to indigestion, muscle pain, fatigue, or another cause responded later (p < 0.0009). Early responders believed their symptoms to be more serious (p < 0.0001), felt more comfortable seeking medical assistance (p < 0.0001), were more anxious or upset when they first noticed symptoms (p = 0.0118), and perceived that they had less control of their symptoms (p < 0.0001) than late responders. A stepwise multiple regression analysis further suggested that unmarried patients responded significantly later than married patients, and patients who first experienced their symptoms at work responded significantly later than those who first experienced their symptoms outside of the home but not at work. These results suggest that situational and psychological variables are important determinants of lengthy decision delays in responding to symptoms of AMI.