VERIFIED CONTENTAuthor: lek. Maciej Grymuza, a graduate of the Faculty of Medicine at the Medical University of K. Marcinkowski in Poznań.
The heart murmur is an auscultation phenomenon associated with turbulent blood flow in the heart and large vessels. A murmur can be detected during a routine medical examination - more often in children than in adults. The murmur is very disturbing, but in many cases unnecessary. What are the types of murmurs that indicate a serious illness, and how do you know if your heart is he althy?
Heart murmursare vibrations that arise when blood flow through the heart valves and blood vessels is disturbed. Detecting a murmur is not the same as diagnosing the disease. The detection of murmurs is understandable, but we should not always be afraid of them.
Heart murmursmay appear physiologically. This is called innocent murmurs that occur in most he althy children and some adults. They do not require further diagnostics, but in case of doubts as to their origin, a cardiac echo is performed.
In adults, newly diagnosed heart murmurs should be more often verified by echocardiography, as they may indicate the presence of valvular defects, which are one of the most common heart diseases.
Murmurs over the heart and the structure and function of heart valves
There are four valves in the heart:
- 2 atrioventricular - between the right atrium of the heart and the right ventricle (trilobal) of the heart and between the left atrium and the left ventricle (bicuspid - mitral),
- 1 between the left ventricle and the aorta
- 1 between the right ventricle and the pulmonary trunk.
All valves are made of a ring and leaflets, and atrioventricular valve leaflets are attached with tendon threads to the papillary muscles in the ventricles.
The valves constantly move according to the heart's cycle and their primary function is to prevent the flow of blood back into the ventricles while the heart beats. During the relaxation of the ventricles, the atria contract, which allows the ventricles to be filled with blood, then the ventricles begin to contract, which causes an increase in pressure in the ventricle and closure of the atrio-valves.chamber.
Blood cannot flow back into the atria - it flows into the aorta or the pulmonary trunk. When the contraction ends, the pressure in the ventricles drops, a small amount of blood begins to regress, causing the aortic and pulmonary valves to close. All valves are essential for the heart to work as efficiently as possible, and you can hear them cyclically closing as the heart sounds. The so-called systolic tone is the result of the closure of the atrioventricular valves, the second - the pulmonary and aortic valves.
Due to various factors: congenital defects, damage, wear and tear, diseases of other organs, but also changes in the structure of the heart cavities (their shape or widening of the vessels coming from the heart), valve dysfunction may occur, i.e. stenosis (stenosis). ) and regurgitation. The first is actually a reduction in the surface area of the mouth, which forces the heart to do more work to pump out the same volume of blood.
Regurgitation also adversely affects the efficiency of the heart - the contraction of the ventricle causes not only the outflow of blood to the aorta or the pulmonary trunk, but also its return to the atrium, so it causes "wasted" part of the ventricular work, and also puts additional strain on the atrium .
Heart murmurs - what are they?
Under normal conditions, blood flows through the vessels and valves in layers (laminar). It is a silent phenomenon. Under certain conditions, however, there is a change in blood flow to the so-called turbulent, characterized by vortices, chaotic flow, and mixing of blood.
The result is vibrations - vibrations of tissues that are heard as murmurs. The situations in which turbulent flow can occur are:
- increasing blood flow through the unchanged vessel,
- normal flow through narrowed outlet or into a dilated vessel,
- regression of blood,
- flow through the abnormal connection between blood vessels.
Heart murmurs - causes
There are 3 types of heart murmurs due to their causes:
- functional murmurs- caused by non-cardiac causes, e.g. anemia or fever,
- innocent murmurs- when no heart disease is found despite the murmur,
- organic murmurs- in the case of heart defects, which may be:
- aortic stenosis,
- aortic regurgitation,
- stenosis of the mitral valve,
- mitral regurgitation,
- leaflet prolapse syndromemitral,
- stenosis of the tricuspid valve,
- tricuspid regurgitation,
- atrial septal defect (ASD),
- oval hole (PFO),
- ventricular septal defect (VSD),
- patent ductus arteriosus (PDA),
- Eisenmenger syndrome (PVD),
- narrowing of the outflow tract of the right ventricle,
- narrowing of the left ventricular outflow tract,
- Ebstein anomaly.
Heart murmurs - types
There are many types of murmurs that are heard depending on the period in which the heart beats (systole or diastole). This typology helps determine which valve the murmur is related to, and whether it is due to regurgitation or stenosis. Based on the phase of the heart's work cycle, we can distinguish between:
- early systolic murmurs- appear at the beginning of ventricular contraction; these may be the so-called innocent murmurs in children, or murmurs indicative of tricuspid or mitral valve insufficiency,
- intracystic murmurs- may appear in the case of stenosis of the valves of the aorta or the pulmonary trunk, less frequently during the fast heartbeat (e.g. during fever),
- late systolic murmurs- audible at the end of a systole, occur very rarely and indicate mitral valve regurgitation in the course of e.g. left ventricular dilatation,
- holosystolic murmurs- are audible throughout the contraction and occur in mitral or tricuspid valve regurgitation, less frequently in ventricular septal defect,
- early diastolic murmurs- audible at the beginning of ventricular relaxation, result from the regurgitation of blood through the aortic valve or the pulmonary trunk and occur in these valve regurgitation,
- intra-diastolic murmurs- appear in various heart defects: mitral and tricuspid stenosis, as well as pulmonary valve regurgitation,
- pre-systolic murmurs- occur in tricuspid or mitral valve stenosis,
- continuous murmurs- are heard during the heartbeat, regardless of the phase; they result from blood flow through abnormal arteriovenous or arteriovenous connections, e.g. in patent Botal's duct,
- a murmur of a venous hum- this is an exceptional murmur because it comes from outside the heart, namely from the internal jugular vein; is often heard in children and pregnant women, and usually does not indicate any pathology.
Depending on the volume and its build-up, murmurs can be classified as:
- increasing murmurs- crescendoas their volume gradually increases,
- decreasing murmurs-decrescendo , i.e. gradually fading away,
- crescendo-decrescendo murmurs- when their volume initially increases and then gradually fades away.
The volume of the murmur is determined on the Levine scale. It has 6 degrees, where 1 is the softest murmur that can be heard, and 6 is a murmur heard with the stethoscope removed from the chest.
When determining a murmur above the heart, it is assessed whether it is a systolic or diastolic murmur, which is often not easy, e.g. during a fast heartbeat. In addition to assessing the phase of its appearance, it is possible to determine the places of the loudest occurrence and radiation, as well as factors increasing the volume of the noise.
On this basis, it is assessed whether the murmur is pathological and a diagnosis can be made with high probability, e.g.
- aortic stenosis causes a systolic murmur over this valve radiating to the carotid arteries,
- mitral regurgitation causes systolic murmur over this valve radiating to the armpit,
- stenosis of the mitral valve causes a diastolic murmur over this valve.
Heart murmurs vs. innocent murmurs
We talk about innocent murmurs when, despite their occurrence, no heart pathologies are found. Innocent murmurs are most common among children in preschool and school age, as well as in adults during fever or in pregnant women. Classifying a murmur as innocent requires the statement of several of its features, namely:
- volume - from 1/6 to 3/6 on the Levine scale,
- Variable volume or fade in during: exertion, emotion, fever,
- no radiation.
The most common innocent murmurs are:
- classical murmur - associated with turbulent blood flow during the outflow from the left ventricle; it is a systolic murmur with a volume of 1-2 / 6,
- pulmonary artery ejection murmur associated with turbulent blood flow during right ventricular outflow, best audible in the supine position,
- venous hum - continuous, heard above the right collarbone due to blood flow in the jugular vein.
Diastolic murmurs are never innocent.
What is the diagnosis and treatment of heart murmurs?
The diagnosis of heart murmurs is based on an interview, which brings in a lot of important information (e.g. on a history of diseases or heart defects in the family), as well as on a physical examination. During auscultation of the heart, the murmur is assessed and classified, and others are searched forabnormalities such as an irregular heartbeat.
Often, after performing this examination, an innocent murmur can be found and further cardiological diagnosis is not necessary. Newly developed murmurs in adults, diagnostic murmurs in children, and murmurs that appear together with other symptoms usually require a more detailed evaluation.
In case of doubt, diagnosis begins with chest X-ray and laboratory tests. They allow for an initial assessment and exclusion of non-cardiac causes of murmurs. An EKG is also helpful in assessing the heart. More detailed diagnostics are carried out by a cardiologist or pediatric cardiologist.
If a cardiac cause of the murmur is suspected, the most important thing is echocardiography. It allows you to visualize this organ, a detailed assessment of anatomy and valves along with the analysis of blood flow. On the basis of this examination, it is possible not only to make a certain diagnosis, but also to state the severity of the defect. Echocardiography also assesses large vessels and the ability of the heart muscle to contract properly.
Further treatment depends on the cause of the murmur:
- innocent murmurs do not require any special treatment, periodic assessment, or functional limitations,
- the treatment of non-cardiac murmurs is based on the treatment of the cause: thyroid disease, anemia or others.
Valve defects, congenital anomalies and structural heart diseases can be treated conservatively - if the disease is good, it is small and asymptomatic. In other cases, cardiac surgery is usually necessary, and in a few diseases it is possible to perform minimally invasive correction - percutaneous (e.g. TAVI).
Bow. Maciej GrymuzaA graduate of the Faculty of Medicine at the Medical University of K. Marcinkowski in Poznań. He graduated from university with an over good result. Currently, he is a doctor in the field of cardiology and a doctoral student. He is particularly interested in invasive cardiology and implantable devices (stimulators).