Congestive Heart Failure

Congestive heart failure (CHF) occurs when the heart does not effectively pump blood, and congestion of the pulmonary and venous system results. Obesity is related to most of the risk factors for developing CHF. Additionally, obesity itself can increase the risk of heart failure. However, it is unclear whether weight loss improves survival after the onset of CHF.

Heart failure involves problems with filling chambers with blood or ejecting blood from chambers. Causes of heart failure include normal aging or underlying cardiovascular disease. The ventricle compensates for dysfunction by hypertrophying or dilating. Compensation negatively affects distensibility and contractility, resulting in a backing up of blood within the circulatory system.

Major risk factors for developing CHF include coronary artery disease, high blood pressure, diabetes, and left ventricular hypertrophy (LVH). Risk factors for prematurely developing CHF include high cholesterol, chronic inflammation, smoking, and genetic factors. Obesity additively clusters risk factors and can result in premature manifestation of CHF. Additionally, obesity causes LVH by increasing blood pressure and viscosity. Overall, obesity is associated with an 8 percent population-attributable risk of developing CHF. Prevention of CHF involves prevention of major risk factors.

The incidence of CHF approximately doubles over each successive decade of life, although the incidence rises more steeply in women. After the age of 40, the lifetime risk of developing CHF is 20 percent. [Page 165]Mortality due to CHF is increasing, partly reflecting the avoidance of death due to predisposing conditions. While obesity increases the risk of developing heart failure, being overweight or mildly obese does not worsen mortality due to CHF while involuntary weight loss increases the mortality due to CHF. Cause of death due to CHF is usually sudden arrhythmic death or progressive pump failure.

Several factors, including obesity and obesity-related illnesses, increase the chance for congestive heart failure.

Major criteria for diagnosing CHF include waking up short of breath, shortness of breath while lying down, increased jugular venous pressure, crackles during lung sounds, a third heart sound, an enlarged heart, and weight loss after treatment with a diuretic. Minor criteria for diagnosing CHF include swelling of the legs, nocturnal cough, shortness of breath on exertion, enlarged liver, and increased heart rate. Patients meeting two major criteria or one major and two minor criteria are considered to have CHF. Imaging measuring heart function confirms CHF diagnosis.

Staging of CHF determines treatment plan. Treatment in all stages involves diet and lifestyle modification, while symptomatic heart failure is treated with medication. Management of CHF involves several classes of heart and vascular drugs as well as drugs for underlying diseases. While weight loss can significantly alleviate underlying risk factors, it is currently unclear if weight loss increases survival rate after onset of CHF. Classification of heart failure is based on function and predicts survival rate.