Plasma N-terminal pro-brain natriuretic peptide and the ECG in the assessment of left-ventricular systolic dysfunction in a high risk population

Abstract

Aims. To examine the value of N-terminal pro-brain natriuretic peptide, abnormal electrocardiogram and other baseline clinical and laboratory variables in identifying patients with left ventricular systolic dysfunction in a high risk population. Methods and Results. We studied 243 patients (129 male, median age 73 years, range 20-94) referred for echocardiography. The relationship between left ventricular wall motion index and log N-terminal pro-brain natriuretic peptide, log creatinine, electrocardiogram, age, history of hypertension, history of ischaemic heart disease, gender, valvular disease and current drug therapy was examined using regression analysis. There was a strong correlation between N-terminal pro-brain natriuretic peptide and left ventricular wall motion index for the whole population (r = -0.624, P < 0.001) and in those receiving diuretic ± angiotensin converting enzyme inhibitor (r = -0.661, P < 0.005) and in those receiving neither (r = -0.584, P < 0.005). On multiple regression analysis, log N-terminal pro-brain natriuretic peptide (P < 0.001), age (P = 0.015), current diuretic (P = 0.002) or angiotensin converting enzyme inhibitor use (P = 0.001) and male gender (P = 0.026) were independently associated with a low left ventricular wall motion index. Log N-terminal pro-brain natriuretic peptide alone (R2 = 39%) was a better predictor of left ventricular wall motion index than any other single or combination of factors. Plasma N-terminal pro-brain natriuretic peptide > 275 pmol l-1 predicted left ventricular wall motion index ≤ 1.2 with a sensitivity of 93.8%, a specificity of 55% and a negative predictive value of 93%. Left ventricular function was impaired in 18/36 patients with a normal electrocardiogram, in all of whom N-terminal pro-brain natriuretic peptide was > 275 fmol ml-1. Conclusion. Of the variables studies, N-terminal pro-brain natriuretic peptide had the strongest correlation with reduced left ventricular wall motion index. The electrocardiogram had a poor predictive value for left ventricular systolic dysfunction in this population. Plasma N-terminal pro-brain natriuretic peptide can usefully predict patients with a reduced left ventricular wall motion index in whom echocardiographic examination may be appropriate.