We measured natriuretic peptides (atrial natriuretic peptide, ANP, brain natriuretic peptide, BNP) in a group of 80 coronary care unit (CCU) patients with unstable angina and acute myocardial infarction (AMI). Patients with clinical signs of heart failure had significantly increased concentrations both of ANP and BNP in comparison to patients without signs of heart failure. The difference was more significant in BNP and on the 3 rd day after admission. One third (32%) of the patients had a normal left ventricular ejection fraction (LVEF) and no clinical signs of heart failure. Approximately 2/3 of these apparently „normal“ patients had increased concentrations of BNP. Two thirds of patients (68%) had either clinical signs of heart failure or decreased LVEF and almost all had increased concentrations of BNP. BNP correlated better with LVEF (r = –0.749) in comparison to ANP (r = –0.341). BNP correlated more closely with the NYHA classification with a wider range of concentrations than ANP. Mean concentrations of BNP in patients with unstable angina (65.1 ng/l) were comparable to that of patients with nonQ-AMI (62.2 ng/l), but the mean concentration of BNP in the Q-AMI group (147.4 ng/l) was twice as high. Only two patients with Q-AMI had normal (below 18.4 ng/l) concentrations of BNP. We conclude that the clinical importance of BNP was superior to that of ANP in CCU patients. BNP had a wide dynamic range of concentra- tions, a better correlation both with clinical status and LVEF. Increased concentrations of BNP were found in patients without evident clinical signs of heart failure and with normal LVEF, indicating thus a high potential of this natriuretic peptide for the classification and management of CCU patients.

        Key words: natriuretic peptides, ANP, BNP, left ventricular ejection fraction, heart failure.