PLE-8317

A 70-year-old nursing home resident is admitted to the hospital because of progressive obtundation over the past 2 days. He has tachycardia, tachypnea, and hypotension. Bilateral basilar crackles and an S3 gallop are heard on auscultation. Examination shows jugular venous distention and peripheral edema. Swan-Ganz catheterization shows a cardiac index of 1.8 L/min/m2 (N=2.5-4.2), a mean pulmonary capillary wedge pressure of 23 mm Hg (N=1-10), and markedly increased systemic vascular resistance. What is the most likely diagnosis?