A 62-year-old woman presented with a 4-month history of persistent and progressively worsening left upper chest pain despite analgesia. One month prior, she had noticed a hoarseness of voice. Physical examination at the time revealed cyanosis, clubbing of hands and feet, and pulmonary regurgitation murmur but no right ventricular failure. There was prominent bulging of her rib cage over the left upper precordium. Cardiac catheterization at 12 years of age had confirmed Eisenmenger syndrome (with mean pulmonary arterial pressure of 86 mm Hg) due to an atrial septal defect and significant shunt reversal. In recent years, she had progressive dilation of her pulmonary arterial trunk despite phosphodiesterase inhibitor treatment for 6 years.A transthoracic echocardiogram revealed an aneurysmal pulmonary arterial trunk with severely elevated right ventricular systolic pressure at 84 mm Hg and right ventricular hypertrophy typical of Eisenmenger syndrome (Figure 1). Computed tomography pulmonary angiogram revealed a giant main pulmonary arterial aneurysm with maximal dimension of 7.2 cm but no radiographic evidence of dissec-