The clinical course of patients with acute myocardial infarction who are unsuitable for thrombolytic therapy because of the presenting electrocardiogram. UK Heart Attack Study Investigators

To examine the clinical characteristics and 30-day fatality rate among patients with electrocardiograms (ECGs) ineligible for fibrinolysis in a consecutive series in four general hospitals in the UK. We studied 2439 consecutive patients who were identified from regular ward visits, surveillance of results from hospital laboratories, and hospital discharge coding. Thirty percent (732) of patients did not have ECGs eligible for fibrinolysis therapy, while indications were uncertain in 55 (2%). Within the ineligible group, patients presenting with ST depression (n = 294) had a higher 30-day fatality rate than those with ST elevation or left bundle branch block (26% versus 17%; P < 0.001); they represented 40% of the group ineligible for fibrinolysis therapy, or 12% of the total cohort. Thirty-day fatality rates in patients presenting with pathological Q waves and no diagnostic ST segment changes (n = 130), those with T wave changes but no other abnormality (n = 168) and those with a normal ECG (n = 128) were 10%, 5% and 3%, respectively. Despite their high fatality rate, fewer patients with ST depression were admitted to coronary care units than those with ECGs eligible for fibrinolysis therapy (61% versus 85%; P < 0.001) and 23% did not receive heparin. The coronary anatomy in a subset of patients with ST depression showed two- or three-vessel disease in 79% and left main stenosis in 9%. The rates of coronary revascularisation were low in all groups (< 10%). Patients with ECGs ineligible for fibrinolysis therapy are a disparate group, with a high rate of fatality occurring in patients who present with ST depression. The high prevalence of multiple vessel coronary disease in patients with ST depression suggests that a more active management strategy is required.