725 Clinical Profiles Associated With Timing of Death in Patients With ST-Elevation Myocardial Infarction: Results of a Province-Wide Field Evaluation

Abstract

While much is known about predictors of mortality in patients with acute ST-elevation myocardial infarction (STEMI), little is known about the the comparative clinical profiles of patients with STEMI who die earlier versus later. Our field evaluation of patients with STEMI in Québec over a 6-month period in 2008-9, in 82 hospitals that treat over 95% of all patients hospitalized with acute myocardial infarction (AMI), provided such an opportunity. We identified all patients who died within a year of presenting to these Québec hospitals with symptoms suggestive of AMI and who had a core-laboratory confirmed STEMI on their presenting electrocardiogram (ECG) or left bundle branch block. Patients who died before they could be admitted were identified by examining all hospital death certificates during this period. Patients who died after a hospital admission were ascertained by linkage to the Québec death registry. The 3 subsets examined were non-admitted deaths (group A), death within 30 days (group B), and death beyond 30 days to 1 year (group C). Information on comorbidities in the 5 years preceding STEMI was obtained by linkage to Québec's medico-administrative databases. Of the 1,852 confirmed STEMI patients, 288 (15.6%) died within 1 year, 53 in group A, 160 in group B, and 75 in group C. Clinical and ECG features of the 3 groups are shown in Table. Group A was younger and had a higher presenting TIMI index (heart rate x [age/10]2 / systolic blood pressure), followed by B, then C. Earliest presentation from symptom onset and more frequent arrival by ambulance was found in group A, followed by B, then C. Presenting ECG features were most severe in A, then B, then C in terms of more anterior STEMI, more leads with ST elevation, highest ST elevation, and more intra-ventricular conduction delay. Q-waves were least frequent in C and most frequent in A. In contrast, patients who died earliest had the least frequent previous hospitalizations, myocardial infarctions, coronary revascularizations and heart failure and generally appeared to have fewer co-morbidities.Tabled 1 STEMI patients who died earlier differed from patients who died later. While they presented more severe acute clinical and ECG features, paradoxically they were younger and appeared to have fewer cardiac and other comorbidities. These findings raise the possibility that previous comorbidities may favor adaptive protective mechanisms at least on intial presention with STEMI.