ARBs directly inhibit the action of angiotensin II by blocking the type 1 receptor, but their effects on bradykinin Oral ACE inhibitors have been shown to reduce symptom- atic heart failure and mortality among patients with previous MI and reduced EF.241 243 Among patients with reduced EF and active or prior heart failure symptoms, ACE inhibitors reduce mortality and heart failure hospitalization, improve New York Heart Association (NYHA) classification, reduce heart size, and prevent the need for escalating medical therapy.244 246 The routine initiation of an ACE inhibitor early after CABG is not recommended for patients with an EF >40%.233 However, it is unlikely that surgical revascularization mitigates the benefits of an ACE inhibitor in the post-CABG patient with a persis- tently reduced EF. Among patients with reduced EF who are intolerant of ACE inhibitors, an ARB can be used as an alternative therapy for those with a prior MI or symptoms of heart failure unless con- Angiotensin II can be generated by alterna- tive pathways, and its production is only partially inhibited by Therefore, concomitant treatment with both an ARB and ACE inhibitor (on a background of -blocker therapy) among patients with reduced EF may be selectively considered in patients with persistent heart failure symptoms and has been shown in clinical trials to reduce cardiovascu- lar death and heart failure hospitalization.252 Nevertheless, the combination of an ACE inhibitor and an ARB should not be used routinely, and this regimen is contraindicated if an aldosterone antagonist is also being used because of increased side effects. These side effects include excessive hypotension, hyperkalemia, and worsening renal function necessitating dis- continuation of therapy.248,249,252 Aldosterone Antagonists Spironolactone is a nonselective aldosterone antagonist that has demonstrated benefits for patients with severe heart fail- ure. 