What causes heart failure?

What causes heart failure?

Heart failure usually occurs when the heart is not able to pump enough blood for the needs of the body. Heart failure can also occur when the heart is not able to relax properly to receive blood so that it can pump out well when it contracts. The former is technically called heart failure with reduced ejection fraction and the later as heart failure with preserved ejection fraction. Ejection fraction is the fraction of the blood within the heart which is pumped out when the heart contracts.

Risk factors for heart disease can also contribute to heart failure as heart failure is the common final pathway for any severe heart disease. Important lifestyle factors in this context are smoking, being overweight, excess amount of fat in blood and sedentary lifestyle. Diabetes, a predominantly lifestyle associated disease, is an important risk factor for heart disease and heart failure.

The most common disease which causes heart failure is coronary artery disease in which there is accumulation of fat deposits within the blood vessels of the heart. This may initially cause chest pain on exertion known as angina and sometimes a heart attack. Heart attack damages the heart muscle and leads to heart failure. Heart attack usually occurs when there is total blockage of a blood vessel supplying oxygenated blood to the heart. The technical term for heart attack is myocardial infarction.

High blood pressure is another important cause for heart failure. Very high blood pressure makes it difficult for the heart to pump blood and leads to heart failure. High blood pressure, known as hypertension, can indirectly cause heart failure by increasing the risk for a heart attack. Good control of blood pressure can prevent heart failure due to hypertension.

Diseases of the heart valves is yet another important cause of heart failure. Abnormalities in heart valves may be present at birth or acquired later due to certain diseases. Rheumatic fever is an important cause of heart valve disease in children. Diseased heart valves can be either leaky, obstructed or a combination of both. Diseased heart valves increase the workload of the heart leading to heart failure later. Heart valves can also get damaged as age advances due to degeneration in the elderly.

Heart muscle disease or cardiomyopathy, leading to heart failure are generally of three types – dilated, hypertrophic and restrictive. In dilated variety the heart muscle is flabby and contracts poorly. Hypertrophic variety is characterised by undue thickening of the heart muscles making it difficult for the heart to relax and receive enough blood to pump out. Restrictive variety also has difficulty in relaxation.

Another important disease of heart muscle is inflammation, known as myocarditis. Myocarditis can occur due to infections caused by viruses, bacteria and other microorganisms. Some vaccines are also associated with myocarditis as an allergic reaction to the heart muscle. Excessive use of alcohol can also weaken the heart muscle.

Birth defects like holes in the wall between chambers of the heart increase the workload of the heart and lead to heart failure later on. An abnormal communication between the largest blood vessels aorta and pulmonary artery can also increase the work load and cause failure. This communication is known as patent ductus arteriosus or PDA in short.

Severe lung disease increases blood pressure in the blood vessels of the lung. When the pressure goes very high, the right ventricle fails. Right ventricle is the lower right chamber of the heart which pumps blood to the lungs. Failure of right ventricle secondary lung disease is called cor pulmonale (cor means heart, pulmonale means related to the lung).

Severe anemia (low levels of hemoglobin in blood), grossly increased function of thyroid glands and severe abnormalities in heart rhythm can lead to heart failure sometimes.