The heart murmur

"You know, I found out I have a heart murmur, the cardiologist says it's nothing serious but I'm still worried"

What is heart murmur, what risks does it involve, when the problem is not a cause for concern? We will try to answer these and other questions in this article on heart murmur.

it consists of several phases, some in which the muscles relax and the valves close, others in which the myocardium contracts and the valve systems open.

To understand well what is meant by heart murmur, it is necessary to know closely the physiology and anatomy of the heart, a very complicated subject that will be treated only marginally in this article (for further information see: Heart: anatomy and physiology).

in fact, they have the important function of guaranteeing the passage of blood in a single direction. An incontinence of these anatomical structures causes a reflux through them which is perceived upon hearing and diagnosed as a heart murmur due to valvular insufficiency.

In medicine, heart murmurs refer to heart noises generated by swirling motions of the blood flow, lasting longer than that of added tones and noises, generated by vibrations of normal or pathological valves and vascular structures

Given the complexity of the heart cycle, it is easy to imagine that there are many other types of heart murmurs. They are classified according to the dynamics (systolic, diastolic, continuous or systolic diastolic), the intensity of the murmurs (six degrees in increasing order of severity), the tonality (high, medium, low) and the phonetic characteristics (aspirated, a rolling, harsh, musical, "seagull cry" etc.)

The anatomo-physiological alterations underlying heart murmurs are numerous and very complex. Noises due to blood flow turbulence can in fact arise due to:

stenosis (narrowing). Condition in which blood flow passes through partial obstruction of a valvular apparatus or arterial vessel (aortic, mitral stenosis, etc.)
insufficient retrograde flow through valve. In these cases, we speak of a regurgitation murmur in which the blood is sucked by an incontinent valve and instead of progressing forward it goes back (triscupid, mitral insufficiency, etc.)
flow in a dilated arterial vessel, for example in the case of aortic aneurysm. Let's take as an example the aortic or lunate valve that blocks the passage of blood into the arterial vessels until the ventricle fills completely. If the aorta is excessively dilated, the valve, despite being of normal size, is unable to completely occlude the orifice which is crossed by a small amount of blood, generating the murmur
flow through cardiac or vascular patents. In these cases some blood passes through small non-physiological holes. This is the case, for example, of the inter-atrial or inter-ventricular septal defect murmurs which normally divide the heart into two distinct halves, preventing any type of communication between the two atria and between the two ventricles
increased flow in normal anatomical structures (ejection murmur in the presence of anemia, hyperthyroidism, exertion, etc). In these cases, the presence of the murmur indicates a non-cardiac pathology

Mitral valve prolapse, just to cite an example, is not a real heart murmur even if it can initially be perceived as such. The disease is in fact caused by the prolapse of one or both valve flaps due to excess tissue and / or the collapse of the tendon structures. This prolapse gives the valve a swollen veil appearance that protrudes inside the atrium. In these conditions a typical noise is generated which is perceived as a shaking (click) similar to that produced by a sail when it flaps. For these reasons the valve is easily incontinent and this can generate a retrograde murmur perceptible upon auscultation.

The passage of blood, pushed by the contraction of the heart, in the large arterial vessels or in the other heart chambers (from the atrium to the ventricle) is constrained by the presence of valves that open and close in relation to the phase of the cardiac cycle. These valves have a reduced caliber compared to the heart chambers and this causes an increase in the speed of the blood flow that passes through them.

This acceleration has repercussions on the anatomical structures crossed, which having a strong elastic component vibrate generating the noise at the base of the heart murmur. When this phenomenon becomes particularly intense (blood flow increases) we speak of GENTLE OR FUNCTIONAL murmurs. Some of these, in addition to having no pathological significance, are temporary and disappear when the conditions that generated them cease (excessive stress, anemia, fever, pregnancy, etc.).

Others, while expressing a slight valve malfunction, are considered completely physiological.

In children, heart murmurs are very frequent (50-60%) and in the vast majority of cases they are classified as "innocent" or as murmurs without pathological significance. To say that a child has an innocent breath is therefore equivalent to saying that his heart is perfectly healthy.