Association of Previous Myocardial Infarction and Time to Presentation With Suspected Acute Myocardial Infarction

Acute myocardial infarction (AMI) remains the leading cause of death worldwide.1 As “time is muscle”, major efforts were undertaken to address patient and system delays and facilitate early diagnosis and revascularization in as many patients with AMI as possible.2,3 Little is known about the impact of medical factors on patient delay. As patient education and patient empowerment to appropriately react to acute chest pain suggestive of AMI are key components in post-AMI cardiac rehabilitation programs, we hypothesized that because of the impact of these educational programs on actual patient behavior, patients with prior AMI would have shorter delays when again presenting with suspected AMI compared with patients without prior AMI.4 This hypothesis was tested in a prospective, multicenter study, including patients presenting with acute chest discomfort to 12 emergency departments (EDs) in 5 countries (Clini calTr ials.gov registry, NCT00470587). The study was approved by local ethic committees. Written informed consent was obtained from all patients.2 Times of chest pain onset (CPO) and chest pain maximum were prospectively assessed by study physicians. Patient delay, as quantified by time from CPO to the ED (CPO-ED) was the primary outcome measure. Time from chest pain maximum to ED presentation was the secondary outcome measure. Time of ED presentation was the time of first vital sign documentation in the ED. Two independent cardiologists adjudicated the final diagnosis, according to the universal definition of AMI.2,3 Patients on long-term dialysis were excluded, according to the study protocol. Sensitivity analyses explored the impact of a history of coronary artery disease (CAD) with or without prior AMI, the impact of sex, and the final adjudicated diagnosis underlying acute chest discomfort (AMI versus other causes). Differences between groups were assessed using Kruskal-Wallis rank-sum test for continuous variables and χ2 or Fisher exact test for categorical variables. The 95% CIs of proportions were constructed using bootstrap. The data have not been made publicly available, but are available from the authors on reasonable request. From April 2006 to April 2018, 6649 patients, 33% women, were eligible for this analysis. Of these patients, 1515 (23%) had a history of prior AMI, and 606 (9%) had a history of CAD, but no prior AMI. CPO-ED was comparable in patients with and without prior AMI (median, 5.0 [interquartile range {IQR},