A 60-year-old man presents to the emergency department with shortness of breath increasing in severity over the past several days, along with paroxysmal nocturnal dyspnea and orthopnea. He does not have a history of heart failure or previous myocardial infarction. On examination it was found that he had a third heart sound and an elevated jugular venous pressure. His chest radiograph showed cardiomegaly (Figure 48-1) and his B-type natriuretic peptide (BNP) was elevated at 600 pg/mL. He was diagnosed with heart failure, evaluated for underlying causes including coronary artery disease, and treated initially with an angiotensin-converting enzyme inhibitor (ACEI) and a diuretic. Later, he will be started on a β-blocker and an aldosterone inhibitor.