Heart murmur: what is it and what are the symptoms?
Many people will have experienced a “heart murmur”, and this expression is often accompanied by a reassuring tone from the doctor who heard it
A heart murmur is generally understood to be an abnormal noise produced by the passage of blood through the heart valves, within the heart cavities or in the major vascular structures near the heart.
But when does a heart murmur require extra attention?
Heart murmur: innocent or organic?
While it is true that a heart murmur is not synonymous with disease, this does not mean that all heart murmurs are the same: in some cases, a heart murmur does not correspond to any objectable pathology (“innocent” heart murmur), while in other situations it may indicate the presence of heart disease that needs to be properly treated or followed up over time (“organic” heart murmur).
Innocent’ heart murmur, also called benign or functional heart murmur, is caused by a high rate of blood transit through the heart structures, triggered trivially by an increase in basal metabolism or an increase in cardiac output.
This type of murmur is not associated with cardiac abnormalities and can occur under certain conditions:
- in the presence of anaemia, fever or excessive stress;
- during pregnancy;
- in cases of excessive thyroid function (hyperthyroidism);
- in healthy sportsmen and women;
- in thin subjects.
This type of murmur is not usually associated with any particular cardiological symptoms, does not limit physical activity or competitive sport, and no special precautions need to be taken, unless the paraphysiological or pathological condition associated with it creates a transient and/or excessive tachycardia or weakness (asthenia), which resolve when the situation that caused them ceases.
The case of organic heart murmur is different
Organic, or pathological, heart murmur is caused by congenital pathologies (present at birth) or acquired pathologies (appearing with age), which modify the structure of the heart or parts of it, such as:
- the heart valves, with malfunctioning of the valve leaflets due to reduced blood flow through the “narrowed” valve (valve stenosis) or due to its imperfect closure with backward blood reflux (valve insufficiency or regurgitation): the causes may be congenital valve malformations, laxity or prolapses of the congenital or acquired valve leaflets leading to valve insufficiency, degenerative senile or post-infectious changes as in endocarditis or with rheumatic fever, or related to autoimmune diseases such as systemic lupus erythematosus (SLE) or rheumatoid arthritis, long radiation treatments;
- the heart muscle (post-infarct or post-inflammatory/post-infiltrative outcomes);
- the septa dividing the right and left cavities of the heart (interatrial or interventricular defects, patency of the foramen ovale) congenital;
- congenital large vessels of the heart (patency of the Botallo’s duct).
Certain diseases present during pregnancy (such as uncontrolled diabetes), viral or bacterial infections contracted especially during the first trimester (especially rubella, cytomegalovirus, cocksackie) or the use of certain drugs (antidepressants such as carbamazepine or lithium, or antiepileptics such as valproic acid and other categories of drugs), drugs and even excessive alcohol taken during gestation can also lead to more or less serious fetal heart malformations and/or valvulopathies.
An abnormal murmur is generally of greater intensity than an innocent murmur and has characteristics that make it easier for the doctor to recognise.
This organic murmur is also more frequently accompanied over time by a series of symptoms which become more or less manifest, depending above all on the severity of the pathology causing it or the speed with which it develops.
They may include
- shortness of breath (dyspnoea)
- swelling in the lower limbs (edema declivum) and sudden weight gain
- enlarged liver
- swelling of the veins in the neck
- chronic coughing
- chest pain on exertion
- dizziness or fainting
- bluish colour (cyanosis) of the skin, especially on the fingers and lips
- poor appetite, growth disturbances, excessive thinness (in infants or young children).
Heart murmur: tests for diagnosis
A heart murmur is discovered by auscultation of the heart’s activity using a stethoscope placed on the chest during a medical examination.
The cardiologist assesses the intensity of the murmur, its location in relation to the heart valves (each valve is best ‘auscultated’ in specific positions in the chest), the time of its appearance in the cardiac cycle and its duration, or the presence of any factors such as breathing or the patient’s position that may alter its characteristics.
Chronic systemic diseases (systemic lupus erythematosus, rheumatoid arthritis, untreated hypertension) or family history of heart disease should also be investigated in order to hypothesise a cause for a pathological murmur (as for example in aortic bicuspidias, which typically runs in families).
In the case of abnormal or persistent murmurs, or even in the case of doubt or motivation related to sporting or occupational fitness (piloting or diving licences), the doctor should request a colour Doppler echocardiogram to define the cause, allow a diagnosis to be made and establish the subsequent clinical-instrumental and therapeutic follow-up, should a pathological murmur be found.
Depending on the outcome of the colour doppler echocardiogram, further instrumental tests may be prescribed, such as :
- a transesophageal echocardiogram
- a cardiac nuclear magnetic resonance scan
- a stress test
- a cardiac angioTAC
- a cardiac catheterization
- a chest X-ray.
Treatment of heart murmur
When the murmur is ‘innocent’ there is no need for further instrumental investigations or special treatment of the cardiovascular system, as the heart is healthy, but if it is associated with an extracardiac disease, such as hyperthyroidism or anaemia, it will disappear by treating the underlying pathology.
Commonly, heart valve disease in its early stages and over many years does not require any drug therapy: even in the case of a mild organic murmur, the cardiologist may only recommend regular echocardiographic checks to monitor the situation and assess whether and when to institute drug therapy over time.
Depending on the cardiac situation and the extent and type of valvulopathy, the following may be indicated
- a prophylactic antibiotic therapy (in true mitral prolapse, in the aftermath of inter-atrial defect and pervious foramen ovale closures, or if already wearing valve prostheses) in the event of surgery, biopsies or complex dental treatment to reduce the risk of infection reaching the heart and valves (bacterial endocarditis);
- treatment with drugs (vasodilators, diuretics, beta-blockers, anti-arrhythmics or anticoagulants) when valve malfunction can begin to compromise the heart’s ability to function properly or requires specific treatment.
- the use of repair or replacement of a diseased valve, which must take place when there is an aggravation of the valvulopathy before it can cause irreversible heart failure or clinical situations of serious discomfort or danger to the patient. Two approaches are possible, a less invasive percutaneous one and a more demanding traditional surgical one.
The minimally invasive percutaneous intervention is performed by inserting catheters into the blood vessels to reach the valve to be repaired (percutaneous transluminal valvuloplasty with balloon catheter) or to be replaced (such as transcatheter aortic valve implantation, ) in the case of major valve stenosis, or by the attachment of special devices to reduce the severity of the valve insufficiency (such as the placement of a ring around the mitral or tricuspid valve or the implantation of Mitraclips under the mitral leaflets).
The actual surgical treatment can either repair the valve by correcting the defective valve apparatus (flaps, ring, cords, papillary muscles) or replace the diseased valve with a biological or mechanical valve prosthesis.
The choice of the type of prosthesis depends on many factors, such as the valve to be replaced, the age of the patient, the degree of physical activity and functional capacity, the lifestyle choices of the person (possible pregnancy, awareness of lifelong anticoagulant therapy in the case of mechanical prostheses, shorter life span of biological valves).
Whenever possible, it is preferred to repair a valve rather than replace it, because valve replacement is associated with better maintenance of cardiac function, better survival and a lower risk of endocarditis, and there is often no need for anticoagulant treatment.
The treatment of cardiovascular risk factors such as hypertension, hypercholesterolemia, diabetes or smoking should also be taken into account, as they can in many cases contribute to aggravating the level of underlying valvulopathy or heart disease, and in any case increase the patient’s overall cardiovascular risk.
Heart murmur: can you do sport?
An innocent heart murmur does not imply any limitation in physical activity or sport, precisely because it is not related to any cardiac or valvular structural pathology.
On the other hand, the prescription of physical exercise in the case of an organic heart murmur due to valvular heart disease depends on the valve involved, the presence and severity of the stenosis or insufficiency, the possible presence of left ventricular dysfunction and/or concomitant coronary artery disease.
Therefore, investigations such as ECG, colour Doppler echocardiogram and stress test or cardiopulmonary test or stress echo are necessary to make a correct assessment of the patient’s functional capacity.
In general, it is recommended that those with a pathological murmur reduce the intensity of physical activity to light or moderate.
Intense, sudden, isometric physical exertion and competitive sports are generally not recommended when valvulopathy becomes moderate, even in the absence of major symptoms.
In patients with moderate-severe or severe valvulopathy, however, it is advisable to recommend, with exceptions, modest aerobic physical activity, walking or gentle exercise, always following the advice of the doctor.
Valvulopathy patients should undergo a programme of adapted physical activity to achieve a gradual and progressive improvement in functional capacity and quality of life.
Aerobic exercises strengthen the heart muscle and make it more efficient.
Aerobic activity does not have to be exhausting: 30 minutes a day of moderate exercise gives a number of benefits, without any particular risks to our health.
Physical activity should therefore always be maintained, but the intensity depends on the heart.