QRS prolongation on surface ECG and brain natriuretic peptide as indicators of left ventricular systolic dysfunction

Abstract

Objective. To determine whether the combination of prolonged QRS duration and brain natriuretic peptide (BNP) levels predicts left ventricular systolic dysfunction (LVSD) with a higher accuracy compared with QRS duration or BNP alone. Setting. University hospital. Methods. We studied 128 consecutive patients with suspected cardiac disease. At rest the QRS duration on 12-lead ECG and BNP levels were determined. A left ventricular ejection fraction (LVEF) <50% at echocardiography was defined as LVSD. Results. QRS duration in the LVSD group (n = 66, LVEF 30 ± 8%) was longer than in the group without LVSD (n = 62, LVEF 60 ± 5%; QRS 129 ± 34 vs. 96 ± 20 ms, P < 0.001). BNP was higher in the LVSD group compared with controls (467 ± 397 vs. 169 ± 242 pg mL-1, P < 0.001). A QRS duration of >0.1, >0.11 or >0.12 s was highly specific (63, 90 and 98%) but less sensitive (84, 81 and 75%) for the prediction of LVSD. A QRS cut-off value of 106 ms was moderately sensitive (65%) but very specific (87%) for the prediction of LVSD, whereas a BNP cut-off value of >84 pg mL-1 was highly sensitive (89%) but only modestly specific (58%). The positive likelihood ratio for LVSD of abnormal BNP (2.0) and QRS prolongation >0.1 s (2.3) was improved by the combination of both criteria (5.1). In multivariate analysis, BNP and QRS duration were independent predictors of LVSD. Conclusions. The combination of abnormal BNP and QRS prolongation yields a higher positive likelihood ratio for the detection of LVSD compared with the two criteria alone.