A Brief Discussion On Heart Murmurs

Heart murmurs are the sounds other than the normal heart sounds produced that is loud enough to be heard with a stethoscope and is caused by turbulence of blood flow across the ehart valves. 

A normal heartbeat makes two sounds like "lub-DUP", which are the normal sounds of the heart valves closing.

The objective of this article is to help the reader understand:

• Taking history and examining a patient with a heart murmur.
• Differential diagnosis for the cause of heart murmur
• Appropriate investigations for a patient presenting with a heart murmur. 

Heart murmurs can be present at birth (congenital) or develop later in life. A heart murmur isn't a disease by itself but the presence of  murmurs may indicate an underlying heart problem. Some murmurs may be benign and are due to conditions outside the heart. These are known as innocent, functional or physiologic murmurs and does not need any treatment. 

Clinical Features: A patient with a heart murmur may present with the symptoms of the underlying heart condition that is causing the murmur. The doctor my detect the presence of the murmur while doing the physical examination. 

Causes: While taking the clinical history it is important to keep in mind the different etiologies that can cause a heart murmur. These may include: 

- Physiologic causes: 

• Anemia
• High blood pressure
• Overactive thyroid
• Fever
• Pregnancy

- Abnormal Heart Murmurs: 

• Septal defects
• Cardiac shunts
• Heart valve abnormalities. 
• Endocarditis 
• Rheumatic fever

Risk Factors: Certain group of people may have risk for developing heart murmurs .These may include: 

• Having a family history of heart disease.
• Autoimmune disorders
• I/V drug abusers  (due to risk of infective endocarditis)
• known history of hypertension. 
• H/o alcoholism, rubella or taking drugs during pregnancy can lead to heart defects in a child leading to heart murmurs. 

Examination: 

A mnemonic to remember what characteristics to look for when listening to murmurs is SCRIPT: 

• Site, 
• Configuration (shape), 
• Radiation, 
• Intensity,
• Pitch & quality, 
• Timing in the cardiac cycle.

Site or Location refers to where the heart murmur is usually heard best. There are four places on the anterior chest wall to listen for heart murmurs; each of the locations roughly corresponds to a specific part of the heart and should be listened to (through the stethoscope) with the patient lying down, face up. The four locations are:
   -Aortic region - the 2nd right intercostal space.
   -Pulmonic region - the 2nd left intercostal spaces.
   -Tricuspid region - the 4th left intercostal space.
   -Mitral region - the 5th left mid-clavicular intercostal space.

Additional maneuvers can be performed for additional auscultation:
    -Left lateral decubitus.
    -With the patient sitting upright.
    -With the patient leaning forward and exhaling.

Shape or Configuration refers to the intensity over time; murmurs can be crescendo, decrescendo or crescendo-decrescendo. Crescendo murmurs progressively increase in intensity. Decrescendo murmurs progressively decrease in intensity. With crescendo—decrescendo murmurs (diamond or kite-shaped murmurs), a progressive increase in intensity is followed by a progressive decrease in intensity.

Radiation refers to where the sound of the murmur radiates. The rule of thumb is that the sound radiates in the direction of the blood flow.

Intensity refers to the loudness of the murmur, 

   -The murmur is only audible on listening carefully for some time.

   -The murmur is faint but immediately audible on placing the stethoscope on the chest.
   -A loud murmur readily audible but with no palpable thrill.   

   -A loud murmur with a palpable thrill.
   -A loud murmur with a palpable thrill. The murmur is so loud that it is audible with only the rim of      the stethoscope touching the chest.
   -A loud murmur with a palpable thrill. The murmur is audible with the stethoscope not touching the      chest but lifted just off it.

Pitch may be low, medium or high and is determined by whether it can be auscultated best with the bell or diaphragm of a stethoscope.

Quality refers to unusual characteristics of a murmur, such as blowing, harsh, rumbling or musical.

Timing refers to whether the murmur is a systolic or diastolic murmur.




Important Characteristics Of Common Murmurs: 

Differential Diagnosis Of Murmurs: 

Workup: A patient with a heart murmur may need further workup and investigations. These may include: 

• Chest X-ray. 
• Electrocardiogram (ECG). 
• Echocardiogram. 
• Cardiac catheterization

Management : depends on the underlying cause.

1. Many children and adults have harmless heart murmurs, which don't need treatment.

2. In case of high blood pressure , it should be controlled by diet, exercise and drugs, like ACE inhibitors, Beta blockers and diuretics.

3. Anticoagulants that prevent clot formation like warfarin, aspirin and clopidogril are given to prevent the risk of stroke or heart attack. 

4. Valve surgery or replacement with prosthetic valves may be needed depending on the underlying valve disease. 

5. Children with congenital heart disease are usually operated to repair the defect.