A 70-year-old man is brought to emergency because of a 2-month history of progressive shortness of breath and fatigue. Vitals are: temperature 98.6 F, HR 100, RR 20, BP 130/80. Examination shows jugular venous distention and crackles in both lung fields. A 2/6 ejection murmur is auscultated at the left sternal border. There is an S3 heart sound. Rectal examination shows dark stool; occult blood is positive. Serum studies are as follows:
Hemoglobin 6 g/dL
WBC 8000/μL
HCO3– 24 mEq/L
Chest x-ray shows an enlarged cardiac silhouette with pulmonary vascular congestion. Ejection fraction is 70%. Which of the following is the most likely cause of these findings?
