Usefulness of B-Type Natriuretic Peptide in Predicting the Involvement of Right Ventricle in Acute Inferior Wall Myocardial Infarction

Abstract

Introduction: Cardiovascular Disease (CVD) is the leading cause of deaths globally as the death rate due to CVD has increased from 26% in 1990 to 29.5% in 2010. The Acute Coronary Syndrome (ACS) includes acute Myocardial Infarction (MI) with ST segment elevation, Non-ST Segment Elevation Myocardial Infarction (NSTEMI) and Unstable Angina (UA). Isolated infarction of the right ventricle is rare and is commonly associated with Inferior Wall MI (IWMI) or Posterior Wall MI (PWMI). B-type Natriuretic Peptide (BNP) is one of the biomarkers which has been evaluated during acute MI. Aim: In this study, the usefulness of BNP in predicting the involvement of Right Ventricle (RV) in acute ST elevation with IWMI and PWMI was assessed. Materials and Methods: The study was a prospective observational study, done on 64 patients less than 60 years of age. The study was conducted over a period of four months at Rajiv Gandhi General Hospital, Madras Medical College, Chennai., Tamil Nadu, India. The patients with diagnosis of IWMI, IW with RVMI, IW with PWMI, IW and PW with RVMI were included. BNP levels, Left Ventricular Ejection Fraction (LVEF) and troponin I were measured. Killip class was also observed and patients were classified and compared against different levels of BNP. Results: When IWMI is associated with RV, PW or RV with PW involvement, BNP level was increased to more than 900 pg/ml, than in isolated IWMI. This increment was statistically significant. There was severe increase in BNP in those having LVEF ≤30%, and majority of patients were in the range of 30-50%. All the patients in Killip class III and IV had severe BNP increase as did those patients with cardiac troponin levels between the range of 2-4 ng/ml. Conclusion: All the findings are statistically significant and prove that severe BNP increase in acute IWMI is definitely a predictor of associated RV, PW or RV with PW involvement. LVEF has a significant inverse correlation with BNP levels, as the BNP rises, LVEF shows a steady decline. Killip class also shows a poor prognosis with elevated BNP. Troponin I levels are higher with increase in BNP.

Keywords

• cardiovascular disease
• left ventricular ejection fraction
• predictor