Congestive Heart Failure

Overview

The term "heart failure" suggests that the heart has stopped working or has "failed." This is not the case. What it actually means is that the heart is working inefficiently, pumping too weakly. When this happens, fluid builds up in the lungs, among other organs, creating a feeling of breathlessness. Heart failure often is referred to as congestive heart failure, or CHF.

Heart failure occurs equally in men and women and is more prevalent among African-Americans, Hispanics, and American Indians than among whites. In the United States, 75 percent to 80 percent of its roughly 5 million victims are older than 65. Each year, nearly 1 million people are hospitalized with CHF, 30 percent to 60 percent of whom are "readmits." The CHF death rate has increased by 35 percent in the past quarter century; the disease is now the main cause or a contributor in nearly 53,000 U.S. deaths each year, according to the American Heart Association. Unfortunately, diagnosis and treatment are often delayed because many people attribute early symptoms of the condition—feeling tired or short of breath—to aging, and so they do not seek immediate treatment.

The rising incidence of heart failure is related to several factors, including an aging population and a lowered death rate for people who have heart attacks. Although treatments for heart attacks have improved, they often damage the left ventricle, the heart's main pumping chamber. In addition, the high rate of obesity in America has escalated the incidence of diabetes and high blood pressure. Both of these conditions make the heart work harder, increasing the risk of heart failure.

Causes of heart failure

Heart failure is caused by conditions that weaken or damage your heart muscle. Six out of every seven patients hospitalized with CHF have a history of coronary artery disease (i.e., heart attacks); three out of four have hypertension, or high blood pressure, and more than half have defective heart valves or a history of diabetes. A heart attack does its damage by suddenly shutting off blood flow to part of the heart muscle. Hypertension, defective heart valves, and diabetes all make the heart work too hard, causing damage over time. A weakened heart, often referred to as cardiomyopathy, also can be inherited or the result of an infection, thyroid disease, and alcohol or drug abuse. Further, the condition can be idiopathic, meaning the cause is unknown.

"Heart failure" encompasses systolic heart failure (SHF) and diastolic heart failure (DHF). Systolic heart failure (or systolic cardiac dysfunction) occurs when the heart muscle contracts with too little force, causing less oxygen-rich blood to be pumped through the body.

Diastolic heart failure (DHF or diastolic dysfunction) occurs when the heart contracts normally but the ventricle walls don't relax enough to let the chamber fill, as it should, and the heart has less blood to pump out. Unlike systolic heart failure, diastolic heart failure occurs more often in women. The mortality rate of DHF is half that of patients with SHF, yet DHF causes as many hospitalizations as SHF. While guidelines for diagnosing and treating SHF have been widely published, little attention has been paid to constructing similar guidelines for DHF.

A test called ejection fraction, which measures the amount of blood in the left ventricle that is pumped out when the chamber contracts, can help determine if systolic or diastolic heart failure is present. A normal ejection fraction is over 50 percent. An ejection fraction of less than 40 percent usually confirms systolic heart failure. Patients with diastolic heart failure, by contrast, can have a normal ejection fraction.

Risk factors

Risk factors for congestive heart failure include:

• Advancing age
• Coronary artery disease and previous heart attacks
• Valve disease
• High blood pressure
• Diabetes
• Thyroid disease
• Irregular heartbeats or arrhythmias
• Serious drug or alcohol abuse