What is Innocent Murmur?
A long time ago, Doctor James Hope was among the first doctors to suggest ways to identify harmless heart murmurs. In his 1942 book, Hope mentioned that these harmless murmurs could easily be differentiated from heart valve disease. As we moved further into the 20th century, it became more widely known among doctors that healthy kids and teenagers might naturally have heart murmurs and rhythms that aren’t signs of disease, especially if the patient isn’t showing any other symptoms.
What Causes Innocent Murmur?
Heart murmurs can be caused by different factors but they all share a single underlying principle called Turbulent Flow.
When we talk about heart murmurs, we sometimes refer to “innocent” murmurs. These are common and often harmless sounds that your doctor might hear when listening to your heart. Innocent murmurs can be heard in different situations such as:
- When there’s an increased turbulent flow. This can happen due to narrower ventricular outflow tracts (the paths through which blood leaves your heart), situations where the heart has to pump more blood such as anemia, and the presence of false tendons in the left ventricle of your heart.
- When there’s a relative narrowing of vessels, for example, during periods when the body is growing rapidly and the vessels are stretching.
- After the lungs expand following birth. This is a condition known as peripheral pulmonic stenosis.
So, whether harmless or harmful, the reason behind heart murmurs boil down to turbulence in the blood flow due to any number of factors. It’s always important to have regular check-ups with your doctor if you have a heart murmur.
Risk Factors and Frequency for Innocent Murmur
Murmurs, or unusual sounds in the heartbeat, are often a reason children are sent to a cardiologist. It’s reported that nearly 72% of children will experience a heart murmur at some time during their youth, and for some, these continue into adulthood while for others, they disappear over time. Many healthcare providers are concerned about not correctly spotting benign murmurs, or harmless heart sounds, that might actually be due to a more serious issue called congenital heart disease (CHD). That said, less than 1% of the general population has congenital heart disease. Furthermore, less than 1% of all new murmurs that lead children to see a cardiologist are due to CHD.
- Murmurs are a common reason for children to see a cardiologist.
- About 72% of children will have a heart murmur at some point in their youth.
- Some of these murmurs may continue into adulthood, while others disappear over time.
- A concern for healthcare providers is wrongly identifying a harmless heart sound as a symptom of congenital heart disease (CHD).
- CHD affects less than 1% of the general population.
- Of all new murmurs seen by a pediatric cardiologist, less than 1% are due to CHD.
Signs and Symptoms of Innocent Murmur
It’s possible to identify and evaluate benign (or harmless) heart murmurs by taking a thorough medical history and conducting a detailed physical examination.
In newborns and infants, medical history includes the mother’s medical history, including her age (as older mothers have a higher risk of offspring with heart defects), any infections she had during pregnancy, and whether she has diabetes mellitus, which is linked to a specific heart disorder called asymmetric hypertrophic cardiomyopathy. The infant’s postnatal history is equally important, especially any feeding difficulties, signs of cyanosis (blueness due to lack of oxygen), or breathing problems. Heart sounds (i.e., murmurs) that are somewhat louder (grade 2/6 or more) in the infant’s first 24 hours of life may indicate heart disease.
In children and adolescents, attention needs to be paid to the child’s activity level. Any decrease in activity level, worsening exercise tolerance, or complaints of shortness of breath, chest pain or fainting with exertion should be taken very seriously.
At the beginning of a physical examination, the doctor will observe the child for any unusual physical features, color changes, signs of difficulty in breathing, and other potential anomalies. Vital signs including blood pressure and pulse oximetry (oxygen levels in the blood) are also measured, and the abdomen checked for signs of heart disease.
The doctor will also listen to the sounds in the child’s heart (auscultation). They will check the timing, intensity, location, quality, pitch, and variation with different body positions of any heart murmurs. Notably, benign murmurs often change significantly with position.
Finally, they will categorize any benign heart murmurs as either systolic ejection murmurs (where blood is forced out of the heart) or benign continuous murmurs, which can be heard throughout the heartbeat cycle. Examples of the former include Stills murmur, innocent pulmonary flow murmur, peripheral pulmonary artery stenosis and arterial supraclavicular murmur. Venous hum and mammary souffle are benign continuous murmurs.
Testing for Innocent Murmur
If your doctor thinks there might be a problem with your heart sounds, they would likely refer you to a heart specialist, also known as a cardiologist. Interestingly, research has shown that chest x-rays and heart electricity tests, also known as electrocardiograms, don’t provide as much helpful information in diagnosing heart murmurs as compared to a proper examination by a heart specialist. If the heart specialist is still worried after they’ve examined you, the next step would typically be to get an echocardiogram, which is a type of ultrasound test that creates a visual picture of the heart. This allows the specialist to see the heart’s structure and check if everything’s in order.
Treatment Options for Innocent Murmur
If a heart murmur is labelled as ‘benign’, it means it’s harmless. These types of murmurs often disappear over time, though in some cases they can last into adulthood without causing any problems. When your doctor tells you that your heart murmur is benign, it means there’s no need to worry or have additional check-ups related to the murmur. You can expect to live a healthy, normal life. However, it’s crucial that this information is recorded in your medical history to avoid unnecessary stress or medical tests in the future. Also, it’s essential to know that if you have a benign murmur, you’re not required to limit your activities or take preventative medicines for heart infections. You can still participate in sports or your regular work without any restrictions.
What else can Innocent Murmur be?
When a doctor is diagnosing chest pain, they might consider several possibilities that may be causing the pain. These conditions include:
- Angina related to atherosclerosis (Hardening of the arteries)
- Aortic stenosis (Narrowing of the heart’s aortic valve)
- Coronary vasospasm (Sudden tightening of the muscles within the arteries of your heart)
- Dissecting aortic aneurysm (A serious condition involving a tear in the large blood vessel branching off the heart)
- Esophagitis (inflammation that may damage tissues of the esophagus)
- Herpes zoster (also known as shingles)
- Hypertrophic cardiomyopathy (A disease in which the heart muscle becomes abnormally thick)
- Musculoskeletal pain (Pain in the muscles, bones, ligaments, tendons, and nerves)
- Myocardial infarction (also known as a heart attack)
- Pericarditis (swelling and irritation of the thin saclike membrane surrounding your heart)
In diagnosing chest pain, it’s important for the doctor to consider all these possibilities and conduct appropriate tests to pinpoint the exact cause.
