Correlation between Cardiac Biomarkers and Right Ventricular Dysfunction in Acute Inferior Wall Myocardial Infarction with and without Right Ventricular Myocardial Infarction

Introduction: Right Ventricular Myocardial Infarction (RVMI) along with inferior wall left ventricular (LV) dysfunction or Inferior Wall Myocardial Infarction (IWMI) is found in 30-50% of the cases. Isolated Right Ventricular (RV) dysfunction or infarction is rare except in iatrogenic (interventional) procedures. RVMI is being more commonly diagnosed retrospectively in the era of primary angioplasty, when these patients post-procedure fail to improve satisfactorily as compared to isolated IWMI patients. Clues to identify early RV involvement in acute IWMI patients will help in better management and less morbidity in this group of patients. Aim: The study was undertaken to search for any correlation between cardiac biomarkers {Troponin I (Trop I), Creatinine Kinase-MB (CK-MB), Brain Natriuretic Peptide (BNP)} and RV involvement using echocardiographic parameters in inferior Acute Myocardial Infarction (AMI), with and without associated RVMI, in patients who underwent primary Percutaneous Coronary Intervention (PCI). Materials and Methods: This was a cross-sectional study, conducted from September, 2018 to August, 2019, in the Cardiology Department of ABVIMS and Dr. Ram Manohar Hospital. A total of 294 patients, presenting with acute IWMI, were included in the study. Samples for Trop-I, CK-MB and BNP were taken immediately after admission. One hundred and thirty two patients had an associated RVMI. Two-dimensional Echocardiography was done within the first 12 hours of admission. Electrocardiography (ECG) and Echocardiography (EEG) assessments were used to determine RV involvement. Comparison was done first between patients with and without RV involvement, followed by comparison among groups for quantitative parameters, especially biomarkers, for finding correlation between biomarker levels and echocardiographic parameters (both RV and LV functions). Results: Patients presenting with IWMI with an associated RVMI had increased LV E/E’ ratio. Also, as predicted, they had a low Tricuspid Annulus Plane Systolic Excursion (TAPSE) and a low RV fractional area change, as well, due to stunning of right ventricle in the acute phase. In the group with higher BNP levels (≥400 pg/mL), the ratio of transmitral Doppler early filling velocity to tissue Doppler early diastolic mitral annular velocity (E/E’) was increased; on the other hand LV ejection fraction and TAPSE were decreased. There was negative correlation between RSm (RV systolic wave), TAPSE and BNP levels. BNP, Trop I and CK-MB levels showed a positive correlation with E/E’ at higher levels. Hypotension was more in patients presenting with RVMI, but it did not reach statistical significance. The mortality was 4.5% in the inferior Myocardial Infarction (MI) with RV involvement group versus 1.8% in isolated inferior MI group (during hospital stay). Conclusion: In acute Inferior wall MI, higher levels of BNP, CK-MB, Trop I, alone or in combination, might be used for prediction of RV involvement. BNP levels ≥400 pg/mL, Trop I levels ≥1.1 ng/mL, and CK-MB levels ≥4.5 ng/mL, along with hypotension and higher E/E’ ratio were observed in such cases and were associated with RV dysfunction and increased mortality.