Heart murmurs are abnormal sounds heard during the cardiac cycle, which can be detected by a healthcare provider using a stethoscope. These sounds are produced by the turbulent flow of blood in the heart or blood vessels and can indicate the presence of an underlying heart condition.
Heart murmurs are classified based on their timing in the cardiac cycle, their loudness, and their location. The timing of a heart murmur is based on when the sound occurs in relation to the normal heart sounds (lub-dub) heard during a heartbeat. Heart murmurs can be systolic, occurring between the first and second heart sounds, or diastolic, occurring between the second and first heart sounds. Heart murmurs can also be continuous, occurring throughout the cardiac cycle.
The loudness of a heart murmur is graded on a scale of 1 to 6, with 1 being very faint and 6 being the loudest. The location of a heart murmur refers to the area of the chest where it is heard most clearly, and it is usually described as the location of the stethoscope where the sound is loudest.
Heart murmurs can also be categorized based on their characteristics, such as their quality, pitch, and radiation. For example, a heart murmur may be described as high-pitched, blowing, or harsh.
Some common causes of heart murmurs include congenital heart defects, valvular heart disease, and abnormalities of the heart muscle or blood vessels. Heart murmurs may also be caused by other medical conditions, such as anemia or hyperthyroidism.
It is important to note that not all heart murmurs indicate a serious underlying condition, and many are harmless. However, if a healthcare provider detects a heart murmur, further evaluation may be necessary to determine the cause and appropriate treatment, if any.
Grading of systolic mumers based on thier intensity
- I/VI: Barely audible
- II/VI: Faint but easily audible
- III/VI: Loud murmur without a palpable thrill
- IV/VI: Loud murmur with a palpable thrill
- V/VI: Very loud murmur heard with stethoscope lightly on chest
- VI/VI: Very loud murmur that can be heard without a stethoscope
a) Systolic ejection murmurs (SEM) are caused by turbulent blood flow resulting from either actual or relative obstruction across the semilunar valves, outflow tracts or arteries. These murmurs are typically heard right after S1 (pulse). The intensity of the murmur increases as more blood flows across an obstruction, resulting in a crescendo-decrescendo or diamond-shaped sound. The most common cause of SEM is innocent murmurs (see below), while other possible causes include stenotic lesions (such as aortic and pulmonary stenosis, coarctation of the aorta, or Tetralogy of Fallot (TOF)), or relative pulmonary stenosis caused by increased flow from an ASD.
b) Holosystolic murmurs, also known as regurgitant murmurs, begin at the start of S1 (pulse) and persist until S2. They are typically caused by conditions such as ventricular septal defect (VSD), mitral valve regurgitation, and tricuspid valve regurgitation.
c) A subtype of holosystolic murmur is the decrescendo systolic murmur, which is sometimes detected in individuals with small ventricular septal defects (VSDs). As the systole progresses, the small VSD may close or reduce in size to the point where blood flow is not discernible, and the murmur becomes inaudible.
Diastolic murmurs:
Murmurs that occur during diastole are typically considered abnormal and can be categorized as early, mid, or late diastolic.
- Early diastolic murmurs are heard immediately following S2 and can be caused by conditions such as aortic and pulmonary regurgitation.
- Mid-diastolic murmurs, also known as rumbles, result from increased flow (relative stenosis) through the mitral or tricuspid valves in conditions such as ventricular septal defect (VSD) or atrial septal defect (ASD).
- Late diastolic murmurs occur due to pathological narrowing of the atrioventricular (AV) valves, with rheumatic mitral stenosis being a common example.
The heart is a complex organ that plays a vital role in circulating blood throughout the body. It consists of four chambers that are separated by valves that regulate the flow of blood in and out of the heart. These valves also help prevent blood from flowing in the wrong direction. A healthy heart makes a “lub-dub” sound as it beats. A heart murmur is an extra sound in the heartbeat — such as a ”whooshing” — that is caused by turbulent blood flow through the heart valves.
This article will explain the causes, symptoms, diagnosis, and treatment of heart murmurs in detail.
Causes of Heart Murmurs
Heart murmurs are caused by turbulent blood flow through the heart valves. This turbulence can occur due to a variety of reasons, such as a damaged or overworked heart valve, a heart defect present from birth, or certain medical conditions that cause the heart to beat faster.
Some common conditions that can cause heart murmurs include:
Anemia: A condition in which the body lacks enough red blood cells to carry oxygen to the body’s tissues.
High blood pressure: A condition in which the force of the blood against the artery walls is too high.
Overactive thyroid: A condition in which the thyroid gland produces too much thyroid hormone, which can cause an increase in heart rate.
Fever: An increase in body temperature that can cause the heart to beat faster.
Heart valve problems that can cause heart murmurs include:
Mitral valve prolapse: Normally, the mitral valve closes completely when the lower left chamber of the heart contracts. It stops blood from flowing back into the upper left chamber. If part of that valve balloons out so it doesn’t close properly, you have mitral valve prolapse. This causes a clicking sound as your heart beats. It’s fairly common and often not serious. But it can lead to the blood flowing backward through the valve, which your doctor may call regurgitation.
Mitral valve or aortic stenosis: Your mitral and aortic valves are on the left side of your heart. If they narrow, which doctors call stenosis, your heart has to work harder to pump blood to the rest of your body. If left untreated, it can wear out your heart and lead to heart failure. You might be born with this. It can also happen as part of aging or because of scarring from infections such as rheumatic fever.
Aortic sclerosis and stenosis: One in three elderly people have a heart murmur because of the scarring, thickening, or stiffening of their aortic valve. That’s aortic sclerosis. It’s usually not dangerous, since the valve can work for years after the murmur starts. It’s sometimes seen in people who have heart disease. But the valve can narrow over time. This is called stenosis. It can lead to chest pain, shortness of breath, or you may pass out. Sometimes, the valve needs to be replaced.
Mitral or aortic regurgitation: In this case, regurgitation means the blood is going the wrong way through your mitral or aortic valve and back into your heart. To counteract it, your heart must work harder to force blood through the damaged valve. Over time, this can weaken or enlarge your heart and lead to heart failure.
Congenital heart defects: About 25,000 babies are born with heart defects each year. These problems include holes in heart walls or abnormal valves. Surgery can correct many of them.
Symptoms
Many people with heart murmurs have no symptoms. But some murmurs can happen along with these other symptoms:
- Chest pain
- Rapid heartbeat (palpitations)
- Breathlessness
- Fatigue
- Bluish skin color or fingertips (sometimes seen in babies with congenital heart defects)
Diagnosis
To diagnose heart murmurs, doctors usually perform a physical examination and listen to the heart using a stethoscope. However, your doctor may order additional tests to determine if your heart murmur is harmless or caused by an acquired valve disease or a congenital defect. These tests may include an electrocardiogram (EKG) to measure the heart’s electrical activity, chest X-rays to detect any enlargement caused by heart or valve disease, and an echocardiogram to create a detailed image of the heart’s structure.
After a thorough examination and testing, if the heart murmur is deemed harmless, no further action may be necessary. However, if the heart murmur is related to a more serious underlying heart condition, your doctor may refer you to a cardiologist. Depending on the cause, medication or surgery may be recommended as treatment.
Treatment
The treatment for heart murmurs depends on the underlying cause. Harmless heart murmurs in many children and adults do not require any treatment. However, if another condition such as high blood pressure is causing the murmur, then your doctor will treat that condition.
For some types of heart valve disease, treatment may involve:
- Medications to prevent blood clots
- Medications to control irregular heartbeat or palpitations
- Medications to lower blood pressure
- Diuretics to remove excess salt and water from your body, making it easier for your heart to pump
- Invasive procedures to correct heart defects present at birth
- Invasive procedures to correct certain types of heart valve disease
In rare cases, doctors may prescribe antibiotics to prevent heart infection before dental work or certain types of surgery.
Prevention
Heart murmurs are typically not preventable, but addressing underlying health conditions, such as high blood pressure, or taking steps to avoid heart valve infections, may help to prevent them from occurring.
It is important to prioritize your health and seek medical advice when needed. If you have a medical concern or question, it is recommended to talk with your doctor. They can provide expert advice and guidance on how to address your specific health needs. By having open and honest communication with your healthcare provider, you can work together to create a personalized plan for your health and well-being. Don’t hesitate to reach out to your doctor if you have any concerns or questions about your health.