Heart failure (HF), often referred to as congestive heart failure (CHF), occurs when the heart is unable to pump sufficiently to maintain blood flow to meet the body's needs.The terms chronic heart failure (CHF) or congestive cardiac failure (CCF) are often used interchangeably with congestive heart failure.Signs and symptoms commonly include shortness of breath, excessive tiredness, and leg swelling.The shortness of breath is usually worse with exercise, while lying down, and may wake the person at night.A limited ability to exercise is also a common feature.
Common causes of heart failure include coronary artery disease including a previous myocardial infarction (heart attack), high blood pressure, atrial fibrillation, valvular heart disease, excess alcohol use, infection, and cardiomyopathy of an unknown cause.These cause heart failure by changing either the structure or the functioning of the heart.There are two main types of heart failure: heart failure due to left ventricular dysfunction and heart failure with normal ejection fraction depending on if the ability of the left ventricle to contract is affected, or the heart's ability to relax.
Signs and Symptoms
Heart failure symptoms are traditionally and somewhat arbitrarily divided into "left" and "right" sided, recognizing that the left and right ventricles of the heart supply different portions of the circulation. However, heart failure is not exclusively backward failure (in the part of the circulation which drains to the ventricle).
Congestive heart failure
Heart failure may also occur in situations of "high output," (termed "high output cardiac failure") where the ventricular systolic function is normal but the heart cannot deal with an important augmentation of blood volume.This can occur in overload situation (blood or serum infusions), kidney diseases, chronic severe anemia, beriberi (vitamin B1/thiamine deficiency), thyrotoxicosis, Paget's disease, arteriovenous fistulae, or arteriovenous malformations.
In developing countries, two to three percent of the population have heart failure, but in those 70 to 80 years old, it occurs in 20–30 percent. More than 20 million people have heart failure worldwide.The prevalence and incidence of heart failure are increasing, mostly because of increasing life span, but also because of increased prevalence of risk factors (hypertension, diabetes, dyslipidemia, and obesity) and improved survival rates from other types of cardiovascular disease (myocardial infarction, valvular disease, and arrhythmias). In the United States, heart failure affects 5.8 million people, and each year 550,000 new cases are diagnosed.