tailieunhanh - Ebook Yale university school of medicine - Heart book: Part 2

Part 2 book presents the following contents: Heart failure, heart muscle disease, heart rhythm disorders, peripheral vascular disease, stroke, women and heart disease, heart disease in the young, heart disease in the elderly, cardiovascular drugs, coronary angioplasty and interventional cardiology,. | CHAPTER 14 HEART FAILURE ROBERT SOUFER . The heart s primary function is to pump blood to all parts of the body bringing nutrients and oxygen to the tissues and removing waste products. When the body is at rest it needs a certain amount of blood to achieve this function. During exercise or times when greater demands are placed on the body more blood is required. To meet these variable demands the heartbeat increases or decreases and blood vessels dilate to deliver more blood or constrict during times when less blood is required. When a person is diagnosed with heart failure it does not mean the heart has stopped working but rather that it is not working as efficiently as it should. In other words the term failure indicates the heart is not pumping effectively enough to meet the body s needs for oxygen-rich blood either during exercise or at rest. The term congestive heart failure CHF is often synonymous with heart failure but also refers to the state in which decreased heart function is accompanied by a buildup of body fluid in the lungs and elsewhere. Heart failure may be reversible and people may live for many years after the diagnosis is made. See box Classifications of Heart Failure. Heart failure may occur suddenly or it may develop gradually. When heart function deteriorates over years one or more conditions may exist See box Effects of Heart Failure. The strength of muscle contractions may be reduced and the ability of the heart chambers to fill with blood may be limited by mechanical problems resulting in less blood to pump out to tissues in the body. Conversely the pumping chambers may enlarge and fill with too much blood when the heart muscle is not strong enough to pump out all the blood it receives. In addition as the architecture of the heart changes as it enlarges regurgitation of the mitral valve may develop making the heart failure even worse. WHO DEVELOPS HEART FAILURE There are an estimated 2 million people in the United States with heart .