A 75-year-old male with a history of myocardial infarction presents to your primary care office with complaints of progressive dyspnea, crackles on physical exam, and cough. The patient is a current smoker with a 60-pack-year history. He has a history of echocardiogram showing an ejection fraction of 50. His electrocardiogram (EKG) is normal and his chest x-ray shows an increased cardiac silhouette, small bilateral pleural effusions, and increased pulmonary vasculature. Which disease process is the patient experiencing