A 58-year-old man with a 10-year history of dilated cardiomyopathy presents to the emergency department with severe dyspnea at rest, orthopnea, and lower limb edema. On examination, he has a blood pressure of 95/60 mmHg, heart rate 110/min, respiratory rate 28/min, and SpO2 78% on room air. Chest X-ray shows bilateral pulmonary edema. Echocardiography confirms left ventricular ejection fraction (LVEF) of 28%. The clinical presentation corresponds to the functional class marked **D** in the diagram. Which of the following is the MOST appropriate INITIAL management approach for this patient?