Pulmonary arterial hypertension is an increasingly recognized condition that occurs sporadically or in association with various diseases. Currently, 6 Food and Drug Administration-approved therapies for this pulmonary vascular disease exist. Patients with pulmonary arterial hypertension can develop right ventricular failure as a result of the natural history of this condition or from an intercurrent illness. The development of right ventricular failure is often suggested by a careful history, physical exam, and ancillary laboratory tests including the electrocardiogram and serum brain natriuretic peptide level. In this setting, echocardiography is a critical screening tool that can assist with the diagnosis. Ultimately, pulmonary artery catheterization establishes the diagnosis of right ventricular failure and provides prognostic information and insight into the adequacy of the pharmacologic interventions via serial cardiopulmonary hemodynamic monitoring.