Pulmonary arterial hypertension (PAH) is a progressive disease that results in elevation of the pulmonary artery pressure and ultimately development of right ventricular failure. Baseline and periodic invasive hemodynamics via right heart catheterization are generally obtained in order to characterize and follow the extent of hemodynamic derangement, response to therapy, and as an end point in clinical trials of novel therapy. Therapy for PAH is steadily evolving, with considerable uncertainty regarding optimal dosing and comparative efficacy of the available therapeutic agents. Ambulatory hemodynamic monitoring techniques are under development that facilitate availability of hemodynamic parameters ad libitum. Such techniques provide novel insights into cardiovascular pathophysiology during activity and may prove to be useful in allowing early detection of hemodynamic changes between clinic visits. Hemodynamics obtained from implantable monitors have been used during PAH medical therapy in pilot studies and could be used as an end point in clinical trials of PAH therapy. Future efforts should focus on proof of clinical utility of implantable monitoring and refinement of cardiac output estimation by pressure waveform analysis.