ATRIAL-NATRIURETIC-PEPTIDE LEVELS AFTER DIFFERENT TYPES OF INFERIOR WALL MYOCARDIAL-INFARCTION

Background: Atrial natriuretic peptide (ANP) is released from cardiac atrium secondary to increased atrial pressure. The plasma levels;of AN P have been found to be related to short- and long-term prognosis afte r acute myocardial infarction (MI). The purpose of the present study w as to investigate the plasma levels of ANP in three groups of patients with inferior wall acute MI classified according to ST-segment depres sion in the precordial leads. Methods: The study population consisted of 18 patients with inferior wall acute MI classified into three types : Type 1 = no precordial ST-segment depression (7 patients), Type 2 = sum of ST-segment depression in leads V-1 to V-3 equal to or more than the sum of ST-segment depression in leads V-4 to V-6 (4 patients), an d Type 3 = maximal precordial ST-segment depression in leads V-4 to V- 6 (7 patients). Results: Radioimmunoassay showed that plasma ANP level s were significantly higher in patients with Type 3 acute inferior wal l myocardial infarction compared with those with Types I and 2 (313.1 +/- 233, 73.0 +/- 27.5), and 84 +/- 32.7 pg/ml, respectively, p = 0.01 8). Conclusions: Plasma ANP levels are higher in patients with Type 3 acute inferior wall MI compared with patients with Types 1 and 2. Thes e findings, together with earlier ones, may contribute to our understa nding of the pathophysiology of the presence of ST-segment depression in the precordial leads in inferior wall acute MI.