© 2016 American College of Cardiology Foundation. Objectives: This study sought to analyze medical therapy data from the CHAMPION (CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in Class III Heart Failure) trial to determine which interventions were linked to decreases in heart failure (HF) hospitalizations during ambulatory pulmonary artery (PA) pressure-guided management. Background: Elevated cardiac filling pressures, which increase the risk of hospitalizations and mortality, can be detected using an ambulatory PA pressure monitoring system before onset of symptomatic congestion allowing earlier intervention to prevent HF hospitalizations. Methods: The CHAMPION trial was a randomized, controlled, single-blind study of 550 patients with New York Heart Association functional class III HF with a HF hospitalization in the prior year. All patients undergoing implantation of the ambulatory PA pressure monitoring system were randomized to the active monitoring group (PA pressure-guided HF management plus standard of care) or to the blind therapy group (HF management by standard clinical assessment), and followed for a minimum of 6 months. Medical therapy data were compared between groups to understand what interventions produced the significant reduction in HF hospitalizations in the active monitoring group. Results: Both groups had similar baseline medical therapy. After 6 months, the active monitoring group experienced a higher frequency of medications adjustments; significant increases in the doses of diuretics, vasodilators, and neurohormonal antagonists; targeted intensification of diuretics and vasodilators in patients with higher PA pressures; and preservation of renal function despite diuretic intensification. Conclusions: Incorporation of a PA pressure-guided treatment algorithm to decrease filling pressures led to targeted changes, particularly in diuretics and vasodilators, and was more effective in reducing HF hospitalizations than management of patient clinical signs or symptoms alone.