ACE inhibitors have been studied extensively in the treatment of heart failure and have been shown to be beneficial in all its stages. Studies with the use of angiotensin receptor blockers (ARBs) in chronic heart failure have not shown equivalent results. Many patients are on an ARB for a variety of reasons. Some of these may have had cough as a symptom of heart failure and not due to medication side effect. According to guidelines, angiotensin converting enzyme inhibitors (ACEi) are still first-line therapy in the treatment of heart failure. As ACEi have been extensively studied showing improvement in morbidity and mortality all patients should be on this treatment unless absolutely contraindicated.

Inclusion Criteria:

• heart failure patients who have indications for ACEi but are currently on ARBs with no absolute contraindications to ACEi
• patients with an ejection fraction of < or = 35% verified in the last 12 months by echo, angio, or nuc med who are NYHA class I to IV and followed in a heart failure clinic for three months
• on beta-blockers, unless contra-indicated
• stable on current meds for 3 months (except dose of diuretics)
• able to give informed consent

Exclusion Criteria:

• documented angioedema/anaphylaxis with prior ACEi use
• documented worsening renal failure, hyperkalemia, cough and gastrointestinal symptoms that are definitely believed to be due to ACEi
• potassium >5.0 mmol/L

heart failure patients followed in heart failure clinics in Canada