OBJECTIVE: To assess left ventricular (LV) function and brain-type natriuretic peptide (BNP) in patients with first-time flash pulmonary edema (FPE). PATIENTS AND METHODS: We retrospectively studied all patients presenting to Mayo Clinic's site in Rochester, MN, from January 5, 2000, to December 30, 2004, with FPE. Only patients with first-time FIRE who had undergone BNP assessment and echocardiography within 24 hours of presentation were included. Patients were divided into 2 groups: those with reduced LV ejection fraction (LVEF) (< 50%) and those with preserved LVEF (>= 50%). RESULTS: Thirty-seven patients met the inclusion criteria (22 female, 15 male). Mean SO LVEF was 41%+/- 13%. The LVEF was reduced in 73% (group 1, n=27; mean SO age, 75 +/- 8 years) and preserved in 27% (group 2, n=10; mean SD age, 75 +/- 13 years). Most frequent underlying causes for first-time FPE were coronary artery disease and hypertension. Patients with preserved LVEF had significantly lower BNP levels at presentation (535 pg/mL [interquartile range, 352-1210 pg/mL]) vs 1320 pg/mL (Inter-quartile range, 768-2000 pg/mL; P=.01.), despite similar elevated LV filling pressures as measured by echocardiography. The mean SO ratio of early diastolic mitral valve inflow velocity to early diastolic mitral annulus velocity was 23 +/- 8 vs 22 +/- 10; P=.78. Early diastolic mitral annulus velocity, a surrogate measurement for myocardial relaxation, was reduced in all patients with preserved LVEF and in 95% of patients with reduced LVEF. CONCLUSION: Coronary artery disease and hypertension are the most common precipitating factors for first-time FPE. Reduced myocardial relaxation in almost all patients regardless of LVEF supports the notion that diastolic dysfunction is a prerequisite for FPE. Levels of BNP were elevated in every patient regardless of LVEF but were significantly lower in patients with preserved LVEF despite similarly elevated LV filling pressures.