Plasma B-type natriuretic peptide in diagnosing inferior myocardial infarction with right ventricular involvement

B-type natriuretic peptide (BNP) is secreted from the ventricles in response to volume expansion and pressure overload. We aimed to investigate plasma BNP levels in inferior myocardial infarction (MI) with and without right ventricular MI (RVMI).

We enrolled 49 patients (mean age: 60+/-10 years, 45 males) who were admitted with first acute inferior MI. Sixteen patients (mean age: 58+/-10 years, 15 males) had also RVMI. The BNP levels were measured at admission. All patients underwent echocardiographic examination in the first day of hospitalization. Receiver-operating characteristic curve was obtained for prediction of inferior MI with RVMI.

Inferior MI with RVMI had lower RV fractional area change (36+/-14% vs. 48+/-15%, P=0.03) and right ventricle lateral annulus S velocity (10.6+/-1.9 m/s, 12.2+/-2.6 m/s, P=0.02). The BNP levels were higher in inferior MI with RVMI than isolated inferior MI (75+/-44 pg/ml vs. 32+/-24 pg/ml, P=0.001). On the basis of the receiver-operating characteristic analysis, the cutoff value of BNP concentration >46 pg/ml provided the best discrimination of patients with and without RVMI (sensitivity 76%, specificity 88%) with positive and negative predictive values of 92 and 63%, respectively.

Plasma BNP levels are higher in inferior MI with RVMI than isolated inferior MI. RV involvement may be suspected when BNP levels are higher than 46 pg/ml in inferior MI.