ABSTRACT: Pulmonary arterial hypertension (PAH) is an increasinglyrecognized cause of dyspnea in elderly patients. Theinitial workup typically includes electrocardiography, chest radiography,echocardiography, and pulmonary function tests. Ifechocardiography shows signs of PAH, the diagnosis should beconfirmed by right heart catheterization. Radiographic evidenceof long-standing PAH includes enlargement of the centralpulmonary arteries with abrupt narrowing of the more distalbranches, giving a "pruned-tree" appearance, and right ventricular(RV) enlargement. The classic radiographic signs of RVenlargement include increased transverse diameter of theheart, elevation of the cardiac border on the posteroanteriorview, and narrowing or loss of the retrosternal airspace on thelateral projection. (J Respir Dis. 2008;29(11):443-450)