ACE indicates angiotensin-converting enzyme; AF, atrial fibrillation; ARB, angiotensin-receptor blocker; COR, Class of Recommendation; DM, diabetes mellitus; GDMT, guideline-directed medical therapy; HF, heart failure; HFpEF, heart failure with preserved ejection fraction; HFrEF, heart failure with reduced ejection fraction; LOE, Level of Evidence; LVEF, left ventricular ejection fraction; MI, myocardial infarction; N/A, not available; NYHA, New York Heart Association; and PUFA, poly- unsaturated fatty acids. JACC Vol. 62, No. 16, 2013 Yancy et al. October 15, 2013:1495 539 2013 ACCF/AHA Heart Failure Guidelines: Executive Summary CLASS IIb 1. The usefulness of implantation of an ICD is of uncertain bene t to prolong meaningful survival in patients with a high risk of nonsudden death as predicted by frequent hospitali- zations, advanced frailty, or comorbidities such as systemic malignancy or severe renal dysfunctiony (268 271). (Level of Evidence: B) 2. CRT may be considered for patients who have LVEF of 35% or less, sinus rhythm, a non-LBBB pattern with a QRS duration of 120 to 149 ms, and NYHA class III/ambulatory class IV on GDMT (254,272). (Level of Evidence: B) 3. CRT may be considered for patients who have LVEF of 35% or less, sinus rhythm, a non-LBBB pattern with a QRS duration of 150 ms or greater, and NYHA class II symptoms on GDMT (253,254). (Level of Evidence: B) 4. CRT may be considered for patients who have LVEF of 30% or less, ischemic etiology of HF, sinus rhythm, LBBB with a QRS duration of 150 ms or greater, and NYHA class I symptoms on GDMT (253,254). (Level of Evidence: C) CLASS III: NO BENEFIT 1. CRT is not recommended for patients with NYHA class I or II symptoms and non-LBBB pattern with a QRS dura- tion of less than 150 ms (253,254,272). (Level of Evidence: B) 2. 