A 58-year-old man with a 10-year history of hypertension and diabetes mellitus type 2 presents with progressive dyspnea on exertion and orthopnea for the past 3 months. On examination, he has a blood pressure of 138/88 mmHg, heart rate 92/min, elevated JVP, bilateral ankle edema, and a displaced apex beat. Chest X-ray shows pulmonary edema. Echocardiography reveals an ejection fraction of 32% with global hypokinesis. He is started on lisinopril and furosemide. After 2 weeks, his symptoms improve but he develops a persistent dry cough. What is the most appropriate next step in his pharmacological management?