Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Left ventricular systolic dysfunction is the condition where the left ventricle can only manage to eject less than 40% (occasionally less than 35%) of the blood in it, with each contraction. The term is used when the echocardiogram shows this but the patient isn’t in overt heart failure.
- Dietary changes
- Operative therapy: Surgery for underlying valvular heart diseases
For patients with systolic dysfunction (EF < 40%) who have no contraindications:
- ACE (angiotensin-converting enzyme) inhibitors for all patients.
- Beta blockers for all patients except those who are hemodynamically unstable, or those who have rest dyspnea with signs of congestion.
- Aldosterone antagonist (low dose) for patients with rest dyspnea or with a history of rest dyspnea or for symptomatic patients who have suffered a recent myocardial infarction.
- Isorbide dinitrates-hydralazine combination for symptomatic heart failure patients who are African-American.
- ARBs (angiotensin receptor blockers) as a substitute for patients intolerant of ACE inhibitors.
- Digoxin only for patients who remain symptomatic despite diuretics, ACE inhibitors and beta blockers or for those in atrial fibrillation.
- Diuretics for symptomatic patients to maintain appropriate fluid balance.
Device based therapy
- Implantable defibrillators considered for prophylaxis against sudden cardiac death in patients with EF ≤ 35%.
- Bi-ventricular pacemakers considered for patients requiring defibrillators who have symptomatic HF and QRS durations ≥ 120 msec.
ACC / AHA Guidelines- Recommendations for Cardiac Resynchronization Therapy in Patients With Severe Systolic Heart Failure (DO NOT EDIT) 
1. For patients who have LVEF less than or equal to 35%, a QRS duration greater than or equal to 0.12 seconds, and sinus rhythm, CRT with or without an ICD is indicated for the treatment of NYHA functional Class III or ambulatory Class IV heart failure symptoms with optimal recommended medical therapy. (Level of Evidence: A)
1. For patients who have LVEF less than or equal to 35%, a QRS duration greater than or equal to 0.12 seconds, and AF, CRT with or without an ICD is reasonable for the treatment of NYHA functional Class III or ambulatory Class IV heart failure symptoms on optimal recommended medical therapy. (Level of Evidence: B)
2. For patients with LVEF less than or equal to 35% with NYHA functional Class III or ambulatory Class IV symptoms who are receiving optimal recommended medical therapy and who have frequent dependence on ventricular pacing, CRT is reasonable. (Level of Evidence: C)
1. For patients with LVEF less than or equal to 35% with NYHA functional Class I or II symptoms who are receiving optimal recommended medical therapy and who are undergoing implantation of a permanent pacemaker and/or ICD with anticipated frequent ventricular pacing, CRT may be considered. (Level of Evidence: C)
1. CRT is not indicated for asymptomatic patients with reduced LVEF in the absence of other indications for pacing. (Level of Evidence: B)
2. CRT is not indicated for patients whose functional status and life expectancy are limited predominantly by chronic noncardiac conditions. (Level of Evidence: C)
- The ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities 
- Shekelle P, Rich M, Morton S, et al. Pharmacologic Management of Heart Failure and Left Ventricular Systolic Dysfunction: Effect in Female, Black, and Diabetic Patients, and Cost-Effectiveness. Evidence Report/Technology Assessment No. 82 (Prepared by the Southern California-RAND Evidence-based Practice Center under Contract No 290-97-0001). AHRQ Publication No. 03-E045. Rockville, MD: Agency for Healthcare Research and Quality. July 2003
- McAlister FA, Ezekowitz J, Dryden DM, Hooton N, Vandermeer B, Friesen C, Spooner C, Rowe BH. Cardiac Resynchronization Therapy and Implantable Cardiac Defibrillators in Left Ventricular Systolic Dysfunction. Evidence Report/Technology Assessment No. 152 (Prepared by the University of Alberta Evidence-based Practice Center under Contract No. 290-02-0023). AHRQ Publication No. 07-E009. Rockville, MD: Agency for Healthcare Research and Quality. June 2007.
- ↑ 1.0 1.1 Epstein AE, DiMarco JP, Ellenbogen KA, Estes NAM III, Freedman RA, Gettes LS, Gillinov AM, Gregoratos G, Hammill SC, Hayes DL, Hlatky MA, Newby LK, Page RL, Schoenfeld MH, Silka MJ, Stevenson LW, Sweeney MO. ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices). Circulation. 2008; 117: 2820–2840. PMID 18483207