MRCP2-0017

A 65-year-old male presents with worsening chest pain on exertion over the past 2 weeks, preventing him from carrying out his daily activities. He has a medical history of hypertension, type 2 diabetes mellitus, sick sinus syndrome, and stable angina. He had a history of excessive alcohol consumption but has been abstinent for the past 9 months after an episode of acute liver decompensation. He previously tried isosorbide mononitrate but experienced significant headaches and facial flushing. He has not had a myocardial infarction before, and a recent echocardiogram showed an ejection fraction of 70%. An ECG shows first-degree heart block with normal QRS complexes at 50 beats/minute, and his blood pressure is 140/76 mmHg. He is currently taking bisoprolol 5mg OD alone and has been using his GTN spray more frequently without relief. What is the most appropriate next step in managing this patient?