Heart failure is the 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 either the right or the left side of the heart: however, it most commonly affects both sides. Heart failure can be acute or chronic (congestive).

HEART FAILURE TYPES AND CAUSES

Left-side heart failure

This may be due to hypertension (high blood pressure), anaemia, hyperthyroidism (over-activity of the thyroid), a heart valve defect (such as aortic stenosis, aortic incompetence, or mitral incompetence), or a congenital heart defect. In all of these conditions, the left side of the heart must work harder than normal to pump the same amount of blood. Sometimes, the heart can compensate for the extra workload by an increase in the size of the left side and in the thickness of its muscular walls, or by an increase in the heart rate. This compensation is only temporary, however, and heart faiulure eventually follows.

Other causes of left-sided heart failure include coronary artery disease, myocardial infarction (heart attack), cardiac arrhythmias (irregularities of heart rhythm) and cardiomyopathy (disease of the heart muscle). In cardiomyopathy, the pumping power of the heart is reduced to a point where it can no longer deal with its normal workload.

Whatever the underlying cause, in left-sided heart failure 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 (excess fluid in the lungs), of which the main symptom is shortness of breath, eventually even when at rest. The patient may awaken at night with attacks pf breathlessness, wheezing, and sweating.

Right-sided heart failure

This is most often caused by pulmonary hypertension (raised blood pressure in the arteries supplying the lungs). This is itself caused by left-sided heart failure, or a lung disease such as chronic obstructive pulmonary disease. Right-sided failure, there is back pressure in the circulation from the heart into the venous system, causing swollen neck veins, enlargement of the liver, and oedema (excess fluid in body tissues), especially swelling of the legs and ankles. In addition, the intestines may become congested, causing discomfort and indigestion.

HEART FAILURE INVESTIGATION AND TREATMENT

Investigation of suspected heart failure may involve a physical examination, X-ray, ECG, and echocardiography. Attacks of acute heart failure may subside of their own accord or may require urgent, life-saving treatment. Immediate treatment of heart failure consists of bed rest, with the patient sitting up. Diuretic drugs are given to increase the output of urine from the kidneys, thereby ridding the body of excess fluid and reducing blood volume. Morphine and oxygen may be given as emergency treatment in acute left-sided heart failure. Long-term drug treatment usually involves the use of ACE inhibitor drugs and diuretics. Angiotensin-II and ant-agonists, other vaso-dilator drugs, and beta-blocker drugs may also be required. If heart failure is associated with atrial fibrillation, digoxin will most likely be prescribed to control the heart rate.

Other possible treatments of heart failure include fitting a pacemaker, coronary artery bypass, and heart transplant.

Source: A-Z family medical encyclopedia by BMA

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