ICD therapy is recommended for primary prevention of sudden cardiac death to reduce total mortality in selected patients with nonischemic dilated cardiomyopathy or ischemic heart disease at least 40 days post-MI with LVEF of 35% or less and NYHA class II or III symptoms on chronic GDMT, who have reasonable expectation of mean- ingful survival for more than 1 yeary (148,249). (Level of Evidence: A) 2. Cardiac resynchronization therapy (CRT) is indicated for patients who have LVEF of 35% or less, sinus rhythm, left bundle-branch block (LBBB) with a QRS duration of 150 ms or greater, and NYHA class II, III, or ambulatory IV symptoms on GDMT. (Level of Evidence: A for NYHA class III/IV (37,250 252); Level of Evidence: B for NYHA class II (253,254). 3. ICD therapy is recommended for primary prevention of sudden cardiac death to reduce total mortality in selected patients at least 40 days post-MI with LVEF of 30% or less and NYHA class I symptoms while receiving GDMT, who have reasonable expectation of meaningful survival for more than 1 yeary (255 257). (Level of Evidence: B) CLASS IIa 1. CRT can be useful 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 III/ambulatory class IV symptoms on GDMT (250 252,254). (Level of Evidence: A) 2. CRT can be useful for patients who have LVEF of 35% or less, sinus rhythm, LBBB with a QRS duration of 120 to 149 ms, and NYHA class II, III, or ambulatory IV symptoms on GDMT (250 254,258). (Level of Evidence: B) 3. 