Q) I went in for my annual checkup and my doctor told me I had a heart murmur after she listened to my chest. What is that and should I be concerned?
A) Heart murmurs are very common and while there’s no reason to panic if you’re diagnosed with one, it is something that should be investigated.
By definition, a heart murmur is an extra sound in the heartbeat. Normally, a healthy heart makes a sound like “lub-dub” as it beats. The “lub” occurs as the heart contracts and the “dub” is heard when the heart relaxes. The murmur is an extra sound that is heard such as a swishing or whooshing that is made when the flow of blood through the heart is more rapid and/ or turbulent than it should be.
To explain why this happens, we’ll do a quick physiology/anatomy refresher to perhaps get a clearer picture of what should be going on. Within the heart there are four different chambers, separated by valves. These valves help prevent the flow from flowing in the wrong direction, (i.e. ideally they are a one-way valve) and control how much blood enters into each chamber during each beat and relaxation of the heart.
De-oxygenated blood is blood that is no longer carrying oxygen since at this point the oxygen has been used up by our assorted organs and muscles in order to fuel their functions. This deoxygenated blood enters the heart through one of the two main veins (the inferior and superior vena cava) and enters into the first chamber, our right atrium.
From there the blood goes through the tricuspid valve to our right ventricle before travelling through the pulmonary valve and into the pulmonary arteries which carries the blood to our lungs to be re-oxygenated once again. The blood then returns to the left atrium of the heart via the pulmonary veins, travels through the mitral valve (also known widely as the bicuspid valve) into the left ventricle, through the last of our heart valves, the aortic valve, before flowing into our aorta which is our largest artery.
Arteries generally carry oxygenated blood to the body and veins carry de-oxygenated blood back to the heart, although the pulmonary versions of these do not follow this rule. From the aorta, the blood starts the journey to the rest of our system.
Going all the way back to our murmur, the “lub” occurs when the heart contracts and the mitral and tricuspid valves close whereas the “dub” occurs when the heart relaxes and the aortic and pulmonary valves close. Heart murmurs can be with you right from birth and thus are termed congenital, a term used for almost any condition we have at birth. They may also develop later in life. Some of those that are first noticed in childhood may be outgrown as the child ages much like asthma and allergies in some kids.
They may also happen just during pregnancy. Heart murmurs such as the ones seen during pregnancy that are harmless are called “innocent” heart murmurs. They are not associated with any medical conditions and do not require any treatments or needed lifestyle changes. People with “innocent” murmurs usually have a structurally normal heart and the change in flow may be caused by such things as:
· Rapid growth (such as during adolescence)
· Anemia (lack of healthy red blood cells that carry oxygen to our tissues)
· Physical activity or exercise
· An overactive thyroid
Innocent heart murmurs may go away with time or continue for the rest of your life without disrupting it in any way.
Unfortunately, not all murmurs can be characterized in this way which is why they should be investigated when detected. In children, a worrisome murmur is usually due to a problem with the heart’s structure such as a hole in the heart (examples include atrial and ventricular septal defects) between two of its chambers or a cardiac shunt that leads to irregular blood flow.
In adults, heart murmurs that raise concerns are usually due to problems related to our valves that develop later in life. Causes of these include:
· Rheumatic fever- an unusual complication of a routine strep throat infection that was not sufficiently treated and goes on to damage a valve.
· Endocarditis- an infection of the inner lining of our heart and valves which has spread there from some other part of our body when it went untreated.
· Calcium deposits (also called calcific or degenerative valve disease).
· Tumors which can form in the heart, just like anywhere else in the body.
· Assorted other medical conditions (Marfan syndrome, lupus, Turner’s syndrome…)
As a result of these, one or more of the valves can become stiff and narrow making it more difficult for the heart not pump blood to the rest of the body. This is called “stenosis”. Or as a result of this stiffness, the valve(s) may not close all the way allowing blood to flow backwards in the heart. This is called regurgitation.
Murmurs are usually first detected by your family physician when they listen to the beating of your heart with a stethoscope. Should they find a murmur, usually there will be some non-invasive follow-up tests such as an echocardiogram which uses sound waves to take a picture of your heart, an electrocardiogram (EKG) which measures the electrical activity of the heart and possibly a chest x-ray or other tests. The murmur is graded from 1-6 if the extra noise occurs when the heart is contracting (1 is very faint & 6 is very loud) or 1-4 if it occurs when the heart relaxes.
Most heart murmurs do not require treatment but if the flow of blood through the heart is significantly altered, the pressure in the heart is too high or the person has symptoms, treatment may be initiated. This may be by prescribing one or more of the many medications commonly used to treat high blood pressure or via surgery to repair or replace a defective valve.
As well, if the murmur is due to an underlying condition such as your thyroid, the cause will naturally be addressed. Most of us have no idea we have a murmur since we may not have any noticeable signs, but some will have one or more of the following symptoms:
· Chest pain
· Bluish skin colour (especially fingertips in babies with congenital heart defects
· Rapid heartbeat/ Palpitations
For more information about this or any other health related questions, contact your pharmacist.