Effect of coronary artery bypass grafting on function of right ventricle in patients with severe left ventricular dysfunction

ObjectivesBoth the ventricles work in synergy creating interdependence. Effect of severe left ventricle dysfunction on right ventricle has not been evaluated. This study is planned to observe incidence and its effect in patients undergoing coronary artery bypass grafting (CABG).MethodsPatients undergoing CABG between July 2009 and July 2010 with LV ejection fraction 40% or less for 6 months were included in this study. Echocardiography parameter of tricuspid annular plane systolic excursion (TAPSE in mm) was used to define right ventricular (RV) dysfunction. TAPSE <15 mm Group I, n = 9 and TAPSE > 15 mm Group II, n = 31.ResultsRV free wall dysfunction (TAPSE <15 mm) was observed in 22.5% patients, which increased to 52.5% following operation. However, comprehensive RV function did not change postoperatively (Myocardial Performance Index, MPI of >0.40 in 42.5% patients preoperatively to 50% cases postoperatively, p = 0.1). Patients in group I have reduced ejection fraction of LV (25% in group I vs 35% in group II, p = 0.03) and higher RV dysfunction (MPI 0.40 in group I vs. 0.19 in group II). Postoperatively, there is worsening of RV and inter-ventricular septum (IVS) function. However, patients with better IVS function preoperatively maintained function postoperatively (r = 0.742, p = 0.001) with better RV function (r = 0.592, p = 0.003).ConclusionRV dysfunction is present in high percentage of patients with severe LV dysfunction. Preserved function of IVS preoperatively is maintained postoperatively and it predicted better postoperative free wall and comprehensive RV function. Proximal block in right coronary artery is associated with free wall RV dysfunction.