Right Ventricular Pressure-Volume Analysis during LVAD Speed Optimization Studies: Insights into Interventricular Interactions and Right Ventricular Failure.

Abstract Background : Interventricular interaction, which refers to the impact of left ventricular (LV) function on right ventricular (RV) function and vice versa, has been implicated in the pathogenesis of RV failure in LVAD recipients. We sought to understand more about interventricular interaction by quantifying changes in right ventricular (RV) systolic and diastolic function with varying LVAD speeds. Methods and Results : Four patients (ages 22-69, 75% male, and 25% with ischemic cardiomyopathy) underwent a protocolized hemodynamic ramp test within 12 months of LVAD implantation where RV pressure-volume loops were recorded with a conductance catheter. The end-systolic PV relationship (ESPVR) and end-diastolic PV relationship (EDPVR) were compared using the V20 and V10 indices (volumes at which ESPVR and EDPVR reach a pressure of 20 and 10 mmHg, respectively). ∆V20 and ∆V10 refer to the change in V20 and V10 from the minimum to maximum LVAD speeds. RV PV loops demonstrated variable changes in systolic and diastolic function with increasing LVAD speed. ESPVR changed in one subject (Subject 2; ∆V20=23.5 mL), reflecting a decline in systolic function with increased speed, and was unchanged in three subjects (average ∆V20=7.4 mL). EDPVR changed with increasing speed in three out of four subjects (average ∆V10=12.5 mL), indicating an increase in ventricular compliance, and remained unchanged in one participant (Subject 1; ∆V10=4.0 mL). Conclusions : Interventricular interaction can improve RV compliance and impair systolic function, but the overall effect on RV performance in this pilot investigation is heterogeneous. Further research is required to understand what patient characteristics and hemodynamic parameters influence the net impact of interventricular interaction.