Heart failure

Inability of the heart to cope with its workload of pumping blood to the lungs and to the rest of the body. Heart failure can primarily affect the right or the left side of the heart, although it most commonly affects both sides, in which case it is known as congestive, or chronic, heart failure. Left-sided heart failure may be caused by hypertension, anaemia, hyperthyroidism, a heart valve defect (such as aortic stenosis, aortic incompetence, or mitral incompetence), or a congenital heart defect (see heart disease, congenital). Other causes of left-sided heart failure include coronary artery disease, myocardial infarction, cardiac arrhythmias, and cardiomyopathy. The left side of the heart fails to empty completely with each contraction, or has difficulty in accepting blood that has been returned from the lungs. The retained blood creates a back pressure that causes the lungs to become congested with blood. This condition leads to pulmonary oedema. Right-sided heart failure most often results from pulmonary hypertension, which is itself caused by left-sided failure or by lung disease (such as chronic obstructive pulmonary disease (see pulmonary disease, chronic obstructive). Right-sided failure can also be due to a valve defect, such as tricuspid incompetence, or a congenital heart defect. There is back pressure in the circulation from the heart into the venous system, causing swollen neck veins, enlargement of the liver, and oedema, especially of the legs and ankles. The intestines may become congested, causing discomfort. Immediate treatment consists of bed rest, with the patient sitting up. Diuretic drugs are given, and digitalis drugs and vasodilators, especially ACE inhibitors, may also be administered. Morphine and oxygen may be given as emergency treatment in acute left-sided failure.