The second myocardial infarction: Is there any difference in symptoms and prehospital delay compared to the first myocardial infarction?

Background: Knowledge is limited concerning the type of symptoms and the time from onset of symptoms to first medical contact at first and second myocardial infarction in the same patient. Aim: This study aimed to describe the type of symptoms and the time from onset of symptoms to first medical contact in first and second myocardial infarctions in men and women affected by two myocardial infarctions. Furthermore, the aim was to identify factors associated with prehospital delays ≥2 h at second myocardial infarction. Methods: A retrospective cohort study with 820 patients aged 31–74 years with a first and a second myocardial infarction from 1986 through 2009 registered in the Northern Sweden MONICA registry. Results: The most common symptoms reported among patients affected by two myocardial infarctions are typical symptoms at both myocardial infarction events. Significantly more women reported atypical symptoms at the second myocardial infarction compared to the first. Ten per cent of the men did not report the same type of symptoms at the first and second myocardial infarctions; the corresponding figure for women was 16.2%. The time from onset of symptoms to first medical contact was shorter at the second myocardial infarction compared to the first myocardial infarction. Patients with prehospital delay ≥2 h at the first myocardial infarction were more likely to have a prehospital delay ≥2 h at the second myocardial infarction. Conclusions: Symptoms of second myocardial infarctions are not necessarily the same as those of first myocardial infarctions. A patient’s behaviour at the first myocardial infarction could predict how he or she would behave at a second myocardial infarction.