PLASMA PROATRIAL NATRIURETIC FACTOR-(1-98) CONCENTRATION AFTER MYOCARDIAL-INFARCTION - RELATION TO INDEXES OF CARDIAC AND RENAL-FUNCTION

Objectives-(a) To assess the relation between plasma concentrations of proatrial natriuretic factor (1-98) and non-invasively derived indice s of left ventricular systolic and diastolic performance and (b) to as sess the potential confounding effect of renal function and age on thi s relation in patients with acute myocardial infarction. Design-Cross sectional comparison of biochemical and echocardiographic indices of c ardiac function. Setting-Norwegian central hospital. Patients-Sixty fo ur patients with acute myocardial infarction. Main outcome measures-Re lation between plasma proatrial natriuretic factor (1-98) concentratio ns and echocardiographic indices of left ventricular systolic function as assessed by univariate and multivariate linear regression analysis . Sensitivity and specificity of plasma proatrial natriuretic factor ( 1-98) concentration as a measure of left ventricular systolic and dias tolic dysfunction. Results-Plasma proatrial natriuretic factor (1-98) concentrations were significantly related to left ventricular ejection fraction (r = -0 . 33; P = 0 . 008), age (r = 0 . 43; P < 0 . 001), a nd creatinine clearance (r = -0 . 53; P < 0 . 001). In a multivariate model left ventricular ejection fraction and creatinine clearance were both independently related to plasma values. The mean concentration o f proatrial natriuretic factor (1-98) was significantly higher in pati ents with an ejection fraction of < 40% than in those with an ejection fraction of greater than or equal to 40% (1876 (1151) v 1174 (530) pm ol/l; P = 0 . 03) and in patients with an abnormal transmitral E/A rat io (< 0 . 65 or > 1 . 65, where E/A is ratio of peak early filling vel ocity to peak atrial component) compared with those with a normal rati o (1572 (895) v 1137 (523) pmol/l, respectively; P = 0 . 02). When pat ients were subdivided according to the median concentration of proatri al natriuretic factor (1192 pmol/l) the sensitivity and specificity we re 89% and 56% respectively for detecting a left ventricular ejection fraction of < 40% and 75% and 61% respectively for detecting an abnorm al E/A ratio. Concentrations below the median had a negative predictiv e value of 97% in excluding an ejection fraction of < 40% and of 84% i n excluding an abnormal E/A ratio. Conclusion-These results suggest th at soon after myocardial infarction left ventricular ejection fraction and indices of renal function are independently related to plasma con centrations of proatrial natriuretic factor (1-98). Plasma concentrati ons of proatrial natriuretic factor (1-98) seem to reflect renal and c ardiac performance rather than specific haemodynamic variables assesse d by noninvasive methods. Plasma proatrial natriuretic factor (1-98) m easurements may be a useful screening tool to identify patients with n ormal cardiac function soon after myocardial infarction.