Heart failure is a medical condition characterized by the inability of the heart to pump sufficient blood to meet the metabolic demands of body tissues or when it is able to do so only at an elevated filling pressure. In other words, when the heart can no longer cope with the needs of the body tissues, it can be said to have failed. Some of the more important causes of heart failure include hypertension, ischaemic heart disease (especially in the western world), valvular heart disease as well as congenital heart diseases, particularly in children.
Evidently, the increasing incidence of this disease nowadays is not unrelated to risk factors like smoking, diabetes mellitus, sedentary lifestyles, excessive alcohol intake and dietary indiscretion among others. Arguably, a basic understanding of the physiology (or functioning) of the heart is fundamental to the recognition of the signs and symptoms of heart failure.
The heart comprises four chambers. The right atrium and right ventricle (right side of the heart) receive deoxygenated blood from the body tissues and deliver it to the lungs for reoxygenation. From the lungs, the fully oxygenated blood is carried to the left atrium and left ventricle (left side of the heart) from where it is subsequently pumped throughout the body to be utilized by the tissues. When the heart is unable to perform this vital function, it is known as left or right heart failure depending on which side is affected. However, in some conditions, both sides of the heart can fail leading to congestive (or biventricular) cardiac failure.