On the first postoperative day, severe dyspnea (classified as New York Heart Association class IV) associated with chest pain suddenly developed in the patient. The physical examination revealed tachypnea (respiratory rate, 26 breaths/min), with pallor, sweating, and cool extremities. Systolic arterial BP was < 80 mm Hg, but the patient responded well to a fluid challenge. He had a sinus tachycardia with a heart rate of 125 beats/min, a temperature of 36.9°C, and oxygen saturation of 98% while breathing 9 L/min oxygen. Chest auscultation was unremarkable. Bedside transthoracic echocardiography (TTE), performed soon after ICU admission, showed right-cavity enlargement (right ventricle [RV], 49 mm; right auricle, 50 mm), with severe RV hypokinesia, paradoxical septal motion, increased vena cava diameter (22 mm) without inspiratory collapse, calculated pulmonary hypertension of 75 mm Hg, LVEF of approximately 20%, and left wall motion similar to that described on previous echocardiographies. The ECG findings were similar to those of the preoperative ECG, with no evidence of acute cardiac ischemia, and the troponin level was normal. Hemodynamic data obtained through a Swan-Ganz catheter included the following: cardiac index, 0.74 L/min/m2; systolic pulmonary artery pressure, 63 mm Hg; diastolic pulmonary artery pressure, 40 mm Hg; mean pulmonary artery pressure, 50 mm Hg; central venous pressure, 28 mm Hg; and wedge pressure, and therefore pulmonary vascular resistance, could not be measured. As a result of these findings, therapy with dobutamine was started at 3 μg/kg/min, and inhaled nitric oxide (NO) at 10 ppm.