Assessment of Right Ventricular function by Echocardiography in patients with Inferior Wall Myocardial Infarction.

Inferior wall myocardial infarction in complicated by right ventricular infarction (RVMI) in as much as 50% of cases. In a series by Anderson et al in 1989, the incidence of RVMI in patients with inferior wall myocardial infarction was between 10 – 50%. Isolated infarction of the right ventricle is extremely rare. Although right ventricular infarction is clinically evident in a sizable number of cases, the incidence is considerably less than that found at autopsy. A major reason for the discrepancy is the difficulty in establishing the presence of RVMI in living patients. Additionally, right ventricular dysfunction and stunning frequently is of a transient nature, such that estimation of its true incidence is even more difficult. Criteria have been set for to diagnose RVMI; but, even when strictly employed, the criteria lead to underestimation of the true incidence of right ventricular infarction. In patients with RVMI, the risk of death in the hospital is high and major complications are greater. Right ventricular infarction contributes markedly to hemodynamic instability, atrio-ventricular conduction blocks, and in-hospital mortality in patients with inferior wall myocardial infarction. Systolic right ventricular function is an important predictor in the course of myocardial infarction. Despite this initial observation nearly two decades ago, this condition has received little clinical attention until recent years. As compared with all clinical variables available at the time of admission, RVMI is associated with a relative risk of in-hospital mortality of 7.7 (95% CI) and a risk of major in-hospital complications of 4.7 (95% CI). The potential hemodynamic derangements associated with right ventricular infarction render the afflicted patient unusually sensitive to diminished preload and loss of atrio ventricular synchrony. These two circumstances can result in a severe decrease in right and, secondarily left ventricular output. AIM OF THE STUDY: To compare various echo methodologies in assessing Right Ventricular function in the setting of Inferior wall myocardial infarction with and without right ventricular involvement. To assess RV function by echocardiography done at different time intervals after the onset of myocardial infarction. To compare RV function in patients who are thrombolysed & those not thrombolysed. To compare RV function in males & females. To compare RV function in different age groups. To assess occult RV dysfunction by echocardiography in patients without Right Ventricular Myocardial Infarction on ECG. CONCLUSIONS: On tissue doppler imaging, right ventricular free wall systolic velocity and early diastolic velocity in patients with RVMI was less compared to patients without RVMI and the correlation was statistically significant. Right ventricular free wall late diastolic velocity and septal velocities did not correlate well with RV dysfunction. Right ventricular myocardial performance index (Tei index) correlated with RV dysfunction and attained statistical significance. Increased MPI values were also associated with higher mortality. Right ventricular dimension & regional wall motion abnormalities were insignificant in detecting RVMI. RV dysfunction was worse in those whose echo was done within 24 hrs, when compared with those done after, showing that RV function improves with time. Thrombolysed patients had lower Myocardial performance index values, compared to those who were not thrombolysed. Age and sex did not significantly correlate with right ventricular function after a myocardial infarction. Echo can identify right ventricular dysfunction in patients who have no or doubtful findings of RVMI on ECG