is a common, costly, and potentially fatal condition, and is the leading cause of hospitalization and readmission in older adults. Heart failure often leads to more drastic health impairments than failure of other, similarly complex organs such as the kidneys or liver. In 2015, it affected about 40 million people worldwide. Overall, heart failure affects about 2% of adults, and more than 10% of those over the age of 70. Rates are predicted to increase. The risk of death in the first year after diagnosis is about 35%, while the risk of death in the second year is less than 10% in those still alive. The risk of death is comparable to that of some cancers. In the United Kingdom, the disease is the reason for 5% of emergency hospital admissions. Heart failure has been known since ancient times, it is mentioned in the Ebers Papyrus around 1550 BCE. Definition Heart failure is not a disease but a syndrome – a combination of signs and symptoms – caused by the failure of the heart to pump blood to support the circulatory system at rest or during activity. It develops when the heart fails to properly fill with blood during diastole, resulting in a decrease in intracardiac pressures or in ejection during systole, reducing cardiac output to the rest of the body. The filling failure and high intracardiac pressure can lead to fluid accumulation in the veins and tissue. This manifests as water retention and swelling due to fluid accumulation (edema) called congestion. Impaired ejection can lead to inadequate blood flow to the body tissues, resulting in ischemia. Signs and symptoms Congestive heart failure is a pathophysiological condition in which the heart's output is insufficient to meet the needs of the body and lungs. The term "congestive heart failure" is often used because one of the most common symptoms is congestion or fluid accumulation in the tissues and veins of the lungs or other parts of a person's body. Congestion manifests itself particularly in the form of fluid accumulation and swelling (edema), in the form of peripheral edema (causing swollen limbs and feet) and pulmonary edema (causing difficulty breathing) and ascites (swollen abdomen). Symptoms of heart failure are traditionally divided into left-sided and right-sided because the left and right ventricles supply different parts of the circulation. In biventricular heart failure, both sides of the heart are affected. Left-sided heart failure is