Rationale: B type natriuretic peptide is known to be elevated (> 100 pg/ml) in patients with heart failure. Furthermore, treatments are available to improve survival and reduce hospitalization if the left ventricular ejection fraction (LVEF) is < 40%. Accordingly, guidelines recommend an LVEF measure for patients with suspected heart failure. Prior work has demonstrated that patients with high BNP values do not always have a measure of left ventricular ejection.