Heart Murmur
The Basics of Heart Function
The heart is an electrical machine. It uses an electrical pulse to pump oxygen-rich blood to the various parts of the body. The heart's pump mechanism is composed of four chambers which are respectively called the left and right atrium, and the left and right ventricles.
Each chamber of the heart has its own job. The right atrium receives the "processed" blood supply from the body, and pushes this blood into the right ventricle. The right ventricle sends the blood into the lungs, where the blood becomes freshly oxygenated. Once the blood is full of oxygen, it re-enters the heart through the left atrium, which is the doorway to the left ventricle. The left ventricle then returns the oxygen-rich blood back to the body. This entire process occurs during the space of a single heartbeat.
Basic Information
When a doctor uses a stethoscope to listen to a heart, he or she can hear the sound of the heartbeat. When the heart is healthy, each heartbeat will generate two sounds. The first sound is the sound of the valve between the atria and the ventricles closing. The second sound is the sound of the valve between the ventricles and the major arteries closing. In the case of a heart murmur, however, an extra, abnormal sound can also be heard. A heart murmur is a series of sounds that are the result of inconsistent blood flow. A doctor can detect the sound of a heart murmur through listening to the heart with a stethoscope. The sounds of a heart murmur last longer than normal heart sounds, and they can be detected between the sounds that typically accompany a normal heartbeat.
Heart murmurs are common in children. In most cases, they are harmless and do not affect a person's overall health. Some health experts estimate that nearly 70 percent of all heart murmurs found in children are produced by a healthy heart and do not require treatment or significant lifestyle changes. In most cases, heart murmurs go away when the affected child reaches adulthood.
There are several different types of heart murmurs. Some heart murmurs are constantly present, while others only occur when the body is active. Heart murmurs that do not pose a serious medical threat are called "innocent" murmurs. Innocent murmurs are soft-sounding, intermittent, and only occur in a very localized region of the chest. At the same time, heart murmurs that are serious medical conditions are called "pathologic" heart murmurs. They may indicate the presence of a severe heart defect. For instance, a pathologic heart murmur may be the result of blood flowing through a damaged heart valve, of a hole in one of the heart's walls, or of congestion in a heart vessel. Pathologic heart murmurs are loud-sounding, continual and may produce a distinct "click" noise.
The Cause of Heart Murmurs
Innocent heart murmurs are typically caused by an irregular flow of blood through the heart. In some instances, anxiety, stress, fever, anemia, overactive thyroid glands and pregnancy can cause innocent heart murmurs.
Pathologic heart murmurs, on the other hand, are caused by underlying defects in the heart or its valves. Valve problems are the more common of the two. The purpose of the valves is to keep blood from flowing backwards into the heart. Thus, a valve defect can lead to blood returning into the heart in the wrong direction, which can disturb the normal blood flow. This disruption of the blood flow results in a heart murmur. Another cause of heart murmurs is an interseptal defect. Interseptal defects refer to a hole in the wall between the left and right sides of the heart. This hole allows blood to flow irregularly through the heart, which results in a heart murmur. Some interseptal holes close up on their own with time, while others must be surgically closed to prevent further damage to the heart.
Symptoms
Most people with heart murmurs have the innocent kind, which are asymptomatic. This means that they do not have recognizable symptoms. Typically, people do not find out that they have this condition until a doctor listens to their heartbeat through a stethoscope. When a person has a pathologic heart murmur (one caused by a structurally defective heart), they may have the following symptoms:
- Shortness of breath
- Dizziness
- Chest pains (angina)
- Palpitations
- Lung congestion
- Fatigue
- Blue coloring of the skin or fingertips
Diagnosis
Typically, heart murmurs are diagnosed when a doctor listens to a heart through a stethoscope. This procedure is called "cardiac auscultation". It is a routine part of a regular check-up. During this procedure, the doctor may ask the person to change their body position and their breathing several times. This is because the sound of a heart murmur changes depending on how the person is positioned and how deeply the person is breathing.
Once the doctor has diagnosed that the person has a heart murmur, the doctor will want to find out if the condition is innocent or pathologic. There are several tests that can help with this further evaluation. In particular, a doctor should use a secondary diagnostic test if the cardiac auscultation reveals a very loud murmur or a distinct clicking sound.
Secondary diagnostic tests for heart murmurs include chest x-rays, electrocardiograms and echocardiograms. A chest x-ray can be used to see if the heart is enlarged. It may also reveal structural abnormalities in the heart. An electrocardiogram (ECG or EKG) can be used to show the heart's activity. It may reveal an enlarged heart, a lack of oxygen, heart damage, irregular heartbeat or any thickening of the cardiac muscle. During an EKG, electrodes are positioned on the person's chest, arms and legs. These electrodes convey impulses of the heart's activity to a machine that produces a graphic reading. The procedure takes approximately ten minutes and routinely occurs in a physician's office. An echocardiogram is a test that can be used to find any structural abnormalities of the heart that may be causing the murmur. It can reveal overall valve function, heart wall motion, and heart size. During this procedure, a sound wave is bounced off of the heart structure and then received by a recording device. The recording device then creates an image of the heart. This test takes about an hour.
Treatment
Treatment for heart murmurs depends on the severity of the murmur. Innocent murmurs rarely require treatment and often go away with time. Regardless, it is a good idea to maintain a healthy lifestyle even if a person only has a mild murmur. A healthy lifestyle includes no smoking, healthy eating, regular exercise and stress reduction.
If a person has a pathologic heart murmur caused by underlying problems, their condition requires treatment. Heart murmurs that are caused by holes in the heart's walls sometimes require surgery to close the hole. Heart murmurs that are caused by valve defects typically require either surgical repair or surgical replacement. In the case of valve surgery, the affected person will be given antibiotics to reduce the risk of bacterial infection during the surgical procedure.
At the same time, medicines are available that can help treat the underlying causes of pathologic heart murmurs. Blood thinners (or anticoagulants) can prevent blood clots from developing. Beta-blockers can slow down rapid heart rates. Antihypertensives can lower blood pressure which reduces stress on the heart. Antiarrhythmics can control irregular heartbeats and reduce the effects of heart palpitations. Diuretics can lower blood pressure. Digoxin can strengthen the power of the heartbeat.