Systolic Murmur

What causes a systolic murmur? Scroll down to learn about the causes, symptoms and treatment of this medical condition.
Under normal circumstances, the human heartbeat sounds like a lub dub. When the mitral and tricuspid valves close at the beginning of the systole, one can hear a 'lub' and when the aortic and pulmonary valves close at beginning of the diastole, a 'dub' sound is heard. Sometimes, unusual swishing or whistling sounds might be heard along with the normal 'lub-dub'. These are referred to as heart murmurs. When the swishing sound is heard during a heart's muscle contraction, it is referred to as a systolic murmur.

Types of Heart Murmurs

The cardiac activity is basically, divided into diastole and systole. Ventricular filling, and a brief period prior to filling, during which the ventricles relax is represented by a diastole. Diastolic murmur is the sound that is heard when the heart muscle relaxes between two heart beats. Systole, on the other hand, represents the time when the heart muscles contract and blood is rejected from the ventricles. Systolic heart murmurs occur between S1 and S2, the first and second heart sounds. The unusual heart sounds that are heard during a systole is divided into early systolic, mid systolic, late systolic and holosystolic murmur. There is another category of murmurs which occur throughout the cardiac cycle, these are referred to as continuous murmurs. Though these heart sounds could be harmless most of the time, sometimes, these could also be indicative of a structural defect in the heart.

Murmurs Heard During a Systole

Causes and Symptoms

As mentioned earlier, heart sounds or murmurs may not be indicative of a heart disease always. Innocent murmurs in infants could be attributed to blood flowing through the heart at a higher speed. These heart sounds or murmurs can also occur during pregnancy. This is caused due to larger volumes of blood flowing through the heart chambers at a high speed. Mid-systolic murmurs generally occur in people suffering from medical conditions such as aortic or pulmonic valve stenosis. Mitral or tricuspid regurgitation, or ventricular septal defects are basically responsible for causing holosystolic heart murmurs. In case of babies, such abnormal heart sounds are generally caused due to congenital heart valve defects.

Medical conditions that could cause such unusual heart sounds in adults include aortic stenosis, endocarditis, mitral regurgitation, mitral valve prolapse, aortic sclerosis, rheumatic fever, thyrotoxicosis or anemia. Aortic valve sclerosis occurs due to formation of calcium deposits on the aortic valve. As a result, the opening of this valve becomes narrow and blood flow to the heart decreases considerably. Blood might also flow at a faster rate due to medical conditions such as anemia, hyperthyroidism and rheumatic fever. In case of people suffering from heart valve disorders, abnormal swishing sounds might also be accompanied by other symptoms such as shortness of breath, rapid heart rate, chest pain, fainting spells, fatigue, bluish skin on lips and fingertips, poor appetite and excessive sweating.


The treatment will vary depending on the underlying cause. If the doctors hear any unusual swishing or whistling sound during the physical examination, they first try to identify whether the heart sounds are innocent or abnormal. Then they would try to identify the type of murmur by assessing the variation in frequency, intensity, pitch, modulation and timing. They try to determine if the murmur is a systolic ejection murmur caused due to an irregular valve or narrowing of vessel. Sometimes, the unusual sounds from the heart might be regurgitant murmur caused due to mitral or tricuspid regurgitation. Only when they are able to identify the underlying cause, they can chalk out the treatment plan.

If these heart sounds are persistent, chest X-rays, cardiac angiography and ECG are generally conducted to check for any valve abnormalities or any heart disease. If these sounds are caused due to anemia, hyperthyroidism or rheumatic fever, these will subside when the underlying cause has been treated. Heart murmurs in children are generally caused due to septal defects. These can be corrected with surgery. Leaky valves or constricted blood vessels in the heart might be corrected with the help of surgical methods. Replacement of valves, closing of holes and enlargement of the blood vessels can be performed to alleviate the symptoms. The doctors might also recommend the use of certain antibiotics for treating this heart problems.

Though unusual swishing sounds that are heard during a heartbeat are harmless in a majority of cases, sometimes these could be indicative of congenital heart defects or other heart problems that might be acquired due to lifestyle-related issues. If your doctor detects an abnormal heart murmur, make sure that you get all the required tests done, to rule out the possibility of a heart disease.
By Smita Pandit
Published: 10/29/2010
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