A healthy heart produces two distinct sounds – lub dub. The ‘lub’ is a sound caused by the mitral and tricuspid valves closing at the beginning of a systole (contraction). The ‘dub’ is the snapping shut of pulmonic and aortic valves, denoting the end of the systole.Here is a demonstration of normal heart sounds, from the University of Washington, Department of Medicine.

Heart murmurs

A heart murmur is an unusual sound that is heard during a heartbeat. Murmurs can be so faint that they are barely noticeable, or considerably loud that they sound like whooshing. A murmur is essentially a swishing sound that is heard when there is an abnormal flow of blood across the heart valve.

‘A murmur is like a fever,’ explains Dr. MadhuSreedharan, Cardiologist and Director of NIMS Heart Foundation, Trivandrum. ‘You have to investigate the reasons for it and then treat it appropriately.’

Causes of heart murmurs

Most heart murmurs are benign and do not require treatment. However, murmurs can also be caused by blood coursing through overworked or damaged heart valves.

‘Murmurs can be either innocent or abnormal. Innocent murmurs do not require any treatment,’ says Dr. Sreedharan.

Innocent heart murmurs

It is not clear why some people have innocent heart murmurs. They’re simply the sounds of blood flowing through the chambers and valves of the heart. Extra blood flowing through the heart, for example during childhood or pregnancy, can cause innocent murmurs there are likely to be benign. Innocent murmurs do not cause symptoms and do not require you to limit activities in any way. A normal murmur may get louder when children run a fever. Treatment is not necessary in most cases, because as the child grows the normal murmurs become progressively difficult to hear.

Abnormal heart murmurs

Abnormal heart murmurs are caused by congenital heart defects or acquired heart valve diseases.

Congenital heart defects

Congenital heart defects are problems with the structure of the heart that are present right at the birth. These defects are commonly found in the interior walls, valves, or arteries and veins that supply blood to the heart. They affect the normal blood flow through the heart.

The defects can range from simple to life-threatening. They are considered to be the most common type of birth defects, and in India, the reported incidence of CHD is eight to 10 out of 1000 births. With the treatment options that are available now, more than 75 per cent of infants born with CHD can survive the first year, and lead relatively normal lives. However, it is important to begin treatment early.

Problems with the heart valve, holes in the heart and problems of the heart muscle are the most common defects that cause abnormal heart murmurs.

Acquired heart valve disease

Acquired heart valve disease is the most common cause of abnormal heart murmurs in the adult population. The disease typically develops as a result of another disorder like rheumatic fever, infections, and age related changes.

Scar tissue formed from a heart attack, injury to the heart, or high blood pressure can enlarge and distort heart valves. Also as you get older, calcium deposits on your heart valves may stiffen and limit the flow of blood. This condition is called sclerosis. A rare but life-threatening infection called Infective Endocarditis may also result in or worsen a heart valve disease.

Source: thehealthsite.com