Echocardiographic assessment of right ventricular function in inferior wall myocardial infarction and angiographic correlation to proximal right coronary artery stenosis.

BACKGROUND: Presence of right ventricular (RV) infarction imposes a higher risk of adverse events in inferior wall myocardial infarction (IWMI). In this study, we attempted to correlate various indices of RV function assessed by echocardiography with presence of a proximal right coronary artery (RCA) stenosis in patients with first episode of acute IWMI.

METHODS: In a prospective study, patients with first episode of acute IWMI underwent echocardiographic assessment within 24 h of symptom onset and indices of RV function viz. RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), myocardial performance index (MPI) and tissue Doppler velocities from RV free wall were measured. Patients who underwent coronary angiogram (CAG) within one month and they were classified into group 1 and group 2 based on the presence or absence, respectively, of a significant proximal RCA stenosis.

RESULTS: There were 90 patients with first episode of IWMI of which 67 patients underwent CAG. There was significant difference between group 1 (n = 26) and group 2 (n = 41) in TAPSE (13.5 ± 1.3 vs 21.3 ± 1.7, p < 0.001), MPI by tissue Doppler (0.87 ± 0.1 vs 0.55 ± 0.2, p < 0.001) and in tissue Doppler systolic velocity from RV free wall (S' 9.8 ± 1.1 vs 15.0 ± 1.5, p < 0.001). There was a good interobserver correlation for TAPSE, MPI by TDI, and S' velocity. TAPSE ≤ 16 (sensitivity 93%, specificity 100%), MPI-TDI ≥ 0.69 (sensitivity 94.7%, specificity 93.5%), S ≤ 12.3 (sensitivity 90.3%, specificity 94.3%) were useful in predicting presence of proximal RCA stenosis.

CONCLUSION: RV function indices like TAPSE, MPI-TDI and S' velocity are useful in predicting proximal RCA stenosis in first episode of acute IWMI.