A 36-year-old woman with known idiopathic dilated cardiomyopathy (confirmed by TTE and angiography) is reviewed in the heart failure clinic. She is NYHA class III. Her current medication is bisoprolol 10 mg od, ramipril 7.5 mg od, spironolactone 25 mg od, digoxin 62.5 micrograms od, furosemide 40 mg bd. She has CRT-D in situ. Her heart rate is 70 bpm and her BP is 85/40 mmHg. She has mild peripheral oedema and a raised JVP. What is your next step?