Abstract Body (Do not enter title and authors here): Right ventricular dysfunction (RVD) with severe tricuspid regurgitation is a major prognostic factor in cardiopulmonary disease, yet the effects of improving tricuspid regurgitation remains unknown. In this study, we evaluated the effects of a novel percutaneous tricuspid valve replacement device (or TVR, Evoque®) on RVD utilizing the right ventricular index of myocardial performance (RIMP, or Tei index). The RIMP encompasses both systolic and diastolic components of right ventricular function. We prospectively analyzed our first 10 patients with severe tricuspid regurgitation undergoing percutaneous TVR. RIMP was measured via echocardiography both before and after percutaneous TVR and compared to normal controls. Patients with RVD had significantly elevated RIMP values (mean 0.55 -/+ 0.08) compared to controls (mean 0.32 -/+ 0.05, p < 0.001). Following percutaneous TVR using the Evoque device, there was a significant reduction in RIMP (mean 0.41 -/+ 0.06, P<0.01), demonstrating an improved global RV function. These findings are correlated with improved invasive hemodynamics and measurements of quality of life. Conclusions: Improving severe tricuspid regurgitation with percutaneous TVR in patients with RVD results in an improvement in global right ventricular function as assessed by the RIMP. This study further highlights RIMP as a reliable marker of RV dysfunction and demonstrates it's responsiveness to interventions that alleviate volume overload from severe TR. Further studies assessing the effect of the improved hemodynamics from percutaneous TVR on patient outcome are ongoing.