Progression of LV dysfunction to clinical heart failure is frequently accompanied by impaired electromechanical coupling, which may further diminish effective ventricular contractility. Modification of ventricular electromechanical delay with cardiac resynchronization therapy (biventricular pacing) can improve ventricular systolic function, amelio- rate functional mitral regurgitation, and in some patients, reduce cardiac chamber dimensions.260 Cardiac resynchroni- zation therapy is generally indicated among patients with an EF <35% in the presence of left bundle-branch block, QRS interval >150 milliseconds, and NYHA class II to IIII heart failure symptoms, and it may be a reasonable therapeutic strategy if the QRS interval is in the 120- to 149-millisecond After 3 months of goal-directed postoperative medical therapy, patients recovering from CABG with these indications should receive an ICD in addition to cardiac resyn- chronization therapy, as detailed elsewhere.260 Previous MI and LV Dysfunction Recommendations 1. In the absence of contraindications, -blockers (biso- prolol, carvedilol, and sustained-release metopro- lol succinate) are recommended after CABG to all patients with reduced EF (<40%), especially among patients with heart failure or those with prior MI (Class I; Level of Evidence A). 2. In the absence of contraindications, ACE inhibitor or ARB therapy (if the patient is ACE inhibitor intoler- ant) is recommended after CABG to all patients with LV dysfunction (EF <40%) or previous MI (Class I; Level of Evidence B). 3. In the absence of contraindications, it is reasonable to add an aldosterone antagonist (on top of -blocker and ACE inhibitor therapy) after CABG for patients with LV dysfunction (EF <35%) who have class NYHA class II to IV heart failure symptoms (Class IIa; Level of Evidence B). 4. 