Congestive heart failure
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Congestive heart failure (CHF) (also called congestive cardiac failure and heart failure) is the inability of the heart to pump a sufficient amount of blood throughout the body, or requiring elevated filling pressures in order to pump effectively.
The term heart failure is frequently misused, especially when given as cause of death: it is not synonymous with "cessation of heartbeat".
There are many different ways to categorize heart failure, including the side of the heart involved (left heart failure vs. right heart failure) or whether the abnormality is due to contraction or relaxation of the heart (systolic heart failure vs. diastolic heart failure).
Individuals with heart failure are sensitive to small shifts in their intravascular volume status (the amount of fluid in their circulatory system). Increasing the volume in their circulatory system can cause symptoms and signs of decompensated heart failure, while decreasing the volume in the circulatory system can cause hypotension.
Signs of decompensated heart failure include pulmonary edema (fluid building up in the lungs), peripheral edema (fluid building up in dependent portions of the body).
Symptoms of decompensated heart failure include dyspnea on exertion (shortness of breath), fatigue, paroxysmal nocturnal dyspnea (shortness of breath when lying down).
The NYHA functional class is a commonly used way to gauge the progression of CHF in a particular patient. This classification is used to determine how much CHF limits their lifestyle, and does not apply to a particular decompensated episode.
Treatment
The treatment of CHF focuses on treating the symptoms and signs of CHF and preventing the progression of disease. If there is a reversible cause of the heart failure (e.g. infection, alcohol ingestion, anemia, thyrotoxicosis, arrhythmia, or hypertension), that should be addressed as well.
Treating the signs and symptoms of CHF involves maintaining a euvolemic state (normal fluid level in the circulatory system). This is done with the judicious use of diuretic agents, vasodilator agents, and positive inotropes. Certain subgroups may benefit from Bi-ventricular pacemaker placement or surgical remodelling of the heart. While these treatment modalities may make the patient symptomatically better, either they have not been shown to improve survival in large clinical studies or those studies have not been performed.
In the recently completed COMPANION trial, cardiac resynchronization therapy (pacing both the left ventricle as well as the right ventricle) has been shown to improve survival in individuals with NYHA class III or IV heart failure with a widened QRS complex on EKG.2
Delaying the progression of heart failure involves the use of ACE inhibitors, beta blockers, and aldosterone inhibitors. These agents have been proven to improve survival in individuals with CHF. While the mechanism of improving is not entirely clear, it appears that these agents prevent remodelling of the heart and therefore prevent progression of dilatation of the left ventricle.
The ultimate treatment is cardiac transplant surgery (heart transplant) or implantation of an artificial heart.
References
1. ACC / AHA guidelines for the Evaluation and Management of Chronic Heart Failure in the Adult (http://www.acc.org/clinical/guidelines/failure/hf_index.htm) (PDF Copy (http://www.acc.org/clinical/guidelines/failure/pdfs/hf_fulltext.pdf))
2. Bristow MR, Saxon LA, Boehmer J, et al for the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) Investigators. Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N Engl J Med 2004; 350:2140-2150.