1.5.4 Offer an angiotensin-converting enzyme inhibitor (or angiotensin receptor blocker if there are intolerable side effects) and an aldosterone antagonist during hospital admission to people with acute heart failure and reduced left ventricular ejection fraction. If the angiotensin-converting enzyme inhibitor (or angiotensin receptor blocker) is not tolerated an aldosterone antagonist should still be offered. In February 2016, the Medicines and Healthcare products Regulatory Agency (MHRA) published advice on the concomitant use of spironolactone and renin-angiotensin system drugs in heart failure concerning the risk of potentially fatal hyperkalaemia. See the MHRA advice for more information. 1.5.5 Closely monitor the person's renal function, electrolytes, heart rate, blood pressure and overall clinical status during treatment with beta-blockers, aldosterone antagonists or angiotensin-converting enzyme inhibitors. 1.6 Valvular surgery and percutaneous intervention The recommendations on valvular surgery and percutaneous intervention have been replaced by the NICE guideline on heart valve disease. 1.7 Mechanical assist devices 1.7.1 At an early stage, the specialist should have a discussion with a centre providing mechanical circulatory support about: people with potentially reversible severe acute heart failure or people who are potential candidates for transplantation. 2 Recommendations for research The Guideline Development Group has made the following recommendations for research, based on its review of evidence, to improve NICE guidance and patient care in the future. In people with acute heart failure, congestion and worsening renal function, does the addition of low-dose dopamine to standard therapy lead to greater diuresis and renal protection compared with adding placebo to standard therapy? Why this is important A randomised controlled trial should be conducted to investigate whether the addition of low-dose dopamine to standard therapy leads to more clinically and cost effective decongestion in people admitted to hospital for treatment of decompensated heart failure. 