[The relationship between plasma BNP level and the left ventricular dysfunction parameters in patients with acute myocardial infarction and it's value in diagonosing heart failure.].

OBJECTIVE: To explore the correlation between plasma BNP level and left ventricular dysfunction parameters in patients with acute myocardial infarction (AMI). METHODS: Plasma BNP level was determined in 230 consecutive inpatients with AMI and 111 normal controls. Patients were grouped according Killip grades, LVEF and LVEDd, respectively. BNP was transformed into lnBNP for the normal distribution. The receiver operator characteristic curve (ROC curve) was drawn to determine the best threshold and criteria for diagnosing heart failure. RESULTS: After AMI, lnBNP levels increased significantly in proportion with increasing Killip grades (I-III), and decreasing LVEF (all P < 0.05). lnBNP level was significantly higher in LVEDd > 55 mm group than in the LVEDd < 55 mm group (P < 0.01). lnBNP, LVEDd and LVEF all linearly correlated with Killip grades (P < 0.05) and the best correlation was shown between lnBNP and Killip grades (r = 0.53, P < 0.05). lnBNP also positively correlated with LVEDd (r = 0.17, P < 0.05) and negatively correlated with LVEF (r = -0.41, P < 0.01). Among the parameters, lnBNP level presented the largest AUC in their ROC curves (P < 0.01) for diagnosing decompensated heart failure and cardiogenic shock. The sensitivity, specifiticity and accuracy rates for diagnosing decompensated heart failure were 84.9%, 45.0% and 70.0% respectively by lnBNP at the cut point of 140 ng/L. The sensitivity, negative predicting value and accuracy rate for diagnosing cardiac shock were 82.8%, 66.7% and 67.4% respectively by BNP at the cut point of 400 ng/L. CONCLUSION: lnBNP level in hospitalized patients with AMI was positively correlated with Killip grades and LVEDd, negatively correlated with LVEF and could serve as a parameter for diagnosing the decompensated heart failure and excluding the cardiac shock.