Background: Elevated left ventricular filling pressure after acute myocardial infarction (AMI) may be identified using clinical assessment, echocardiography, and B-type natriuretic peptide (BNP) levels. All of these predict outcome in this setting. There are, however, no data assessing their relative prognostic value. The current study addresses this. Methods: Four hundred patients underwent detailed echocardiography and measurement of BNP levels after AMI (median 1 day). The study end points were (1) a composite of death, recurrent AMI, and/or admission to hospital with heart failure within 1 year and (2) all-cause mortality during medium-term follow-up (median 2.9 years). Results: Both an elevated ratio of early transmitral flow to early mitral annulus velocity (E/e') and higher BNP levels were associated with an increased risk of an adverse event within the first year (odds ratio 6.14 for E/e' >15, P <.001; odds ratio 1.19 per 50-pg/mL increase in BNP, P <.001) and medium-term mortality (hazard ratio 4.67 for E/e' >15, P <.001; hazard ratio 1.10 per 50-pg/mL increase in BNP, P <.001). Among patients with BNP levels higher than the median or in the upper quartile, an E/e' ratio >15 identified a subgroup at greatest risk of mortality (P <.001 for both). Conclusions: The E/e' ratio and BNP levels play important and complementary roles in the risk stratification of patients after AMI. © 2010 Mosby, Inc. All rights reserved.