First-line treatment 1.4.1 Offer an angiotensin-converting enzyme (ACE) inhibitor and a beta-blocker licensed for heart failure to people who have heart failure with reduced ejection fraction. Use clinical judgement when deciding which drug to start first. [2010] ACE inhibitors 1.4.2 Do not offer ACE inhibitor therapy if there is a clinical suspicion of haemodynamically significant valve disease until the valve disease has been assessed by a specialist. See the section on referral for echocardiography and specialist assessment in the NICE guideline on heart valve disease. [2003] 1.4.3 Start ACE inhibitor therapy at a low dose and titrate upwards at short intervals (for example, every 2 weeks) until the target or maximum tolerated dose is reached. [2010] 1.4.4 Measure serum sodium and potassium, and assess renal function, before and 1 to 2 weeks after starting an ACE inhibitor, and after each dose 1.4.5 Measure blood pressure before and after each dose increment of an ACE inhibitor. Follow the recommendations on measuring blood pressure, including measurement in people with symptoms of postural hypotension, in the NICE guideline on hypertension in adults. [2018] 1.4.6 Once the target or maximum tolerated dose of an ACE inhibitor is reached, monitor treatment monthly for 3 months and then at least every 13 of 6 months, and at any time the person becomes acutely unwell. [2010, Alternative treatments if ACE inhibitors are not tolerated 1.4.7 Consider an ARB licensed for heart failure as an alternative to an ACE inhibitor for people who have heart failure with reduced ejection fraction and intolerable side effects with ACE inhibitors. [2010] 1.4.8 Measure serum sodium and potassium, and assess renal function, before and after starting an ARB and after each dose increment. [2010, 1.4.9 Measure blood pressure after each dose increment of an ARB. 