Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure.

BACKGROUND B-type natriuretic peptide is released from the cardiac ventricles in response to increased wall tension. METHODS We conducted a prospective study of 1586 patients who came to the emergency department with acute dyspnea and whose B-type natriuretic peptide was measured with a bedside assay. The clinical diagnosis of congestive heart failure was adjudicated by two independent cardiologists, who were blinded to the results of the B-type natriuretic peptide assay. RESULTS The final diagnosis was dyspnea due to congestive heart failure in 744 patients (47 percent), dyspnea due to noncardiac causes in 72 patients with a history of left ventricular dysfunction (5 percent), and no finding of congestive heart failure in 770 patients (49 percent). B-type natriuretic peptide levels by themselves were more accurate than any historical or physical findings or laboratory values in identifying congestive heart failure as the cause of dyspnea. The diagnostic accuracy of B-type natriuretic peptide at a cutoff of 100 pg per milliliter was 83.4 percent. The negative predictive value of B-type natriuretic peptide at levels of less than 50 pg per milliliter was 96 percent. In multiple logistic-regression analysis, measurements of B-type natriuretic peptide added significant independent predictive power to other clinical variables in models predicting which patients had congestive heart failure. CONCLUSIONS Used in conjunction with other clinical information, rapid measurement of B-type natriuretic peptide is useful in establishing or excluding the diagnosis of congestive heart failure in patients with acute dyspnea.