A 46 year old man presents with a 2 month history of intermittent shortness of breath and bilateral lower leg swelling. On examination, he has no audible cardiac murmurs, and his blood pressure is 123/64 mmHg. Further investigations reveal his NT-pro-BNP level is 745 pmol/L (range 47-236 pmol/L) and echocardiography demonstrates an ejection fraction of 32%.
Given the likely diagnosis, what is the most appropriate initial treatment option?
