Stenosis of the left atrioventricular orifice

May 28, 2018 17:15 | Disease Treatment
Pathology .In itself, "pure mitral stenosis" in childhood is very rare. On our own material, it was observed in 3.2% of cases. However, the narrowing of the left atrioventricular orifice complicated by the failure of the valves is common, and most of our material( 53.42%) represented exactly these cases. Of these, only combined mitral malformation was observed in 46.36%, and in the remaining 7.26% of cases, aortic and tricuspid valve changes were also observed.

The question of whether there is "mitral insufficiency" and "mitral stenosis" by themselves, or one can only talk about a mixed state related to the notion of the so-called "mitral disease" is still controversial. In our opinion, we, the pediatricians, can rightfully speak on this issue, because the cause of heart defects, rheumatic fever, is practically a childhood illness. Therefore, we often see the appearance of vices. If we consider the so-called "mitral disease" in its origin, in dynamics, then we can establish that in most of the cases the disease begins with insufficiency. This is understandable, because for the distortion of the edges of the valves a very short time is enough. Later, when the edges of the valves gradually coalesce, along with the still predominant insufficiency, stenosis also arises. In the clinic, we repeatedly had the opportunity to observe such a transition from one to the other - the insufficiency of bivalves and stenosis. On our sectional material and on the clinical material observed by us with the help of phonocardiograms, in all cases, first there was insufficiency, and followed by the beginning stenosis. In childhood, the process is usually suspended here and only very rarely progresses to pure stenosis. While insufficiency manifests itself in the first months of the disease, it usually takes 1-2 years to develop a combined heart disease. Pure stenosis rarely develops before 2-5 years.(Appearing during carditis and later disappearing proto-diastolic murmur of relative stenosis can be assessed only in the mirror of time.) In fact, in several stages, a combined heart disease develops. If insufficiency prevails to the end, then with age, the clinical picture almost does not change. In other cases with increased stenosis, insufficiency gradually loses its significance, and a combined mitral malformation with predominance of stenosis or pure stenosis occurs. In the case of dominant stenosis, there is still a reverse blood flow, except when the orifice is located near the anterior lateral adhesion, when the wall of the left ventricle, when contracted, can clog the hole. In such cases, the failure of the valves can remain clinically hidden. There are also such patients with pure "mitral stenosis", which can not be traced back to this process. The same can be seen on the basis of a large therapeutic material.

The morphological pattern is determined by the fact that the cause of the change - with the exception of congenital cases - is almost without exception rheumatic fever. The edges of the valves are thick, uneven, the valves are stubborn, cicatrical splices and puckering of the valves are observed. The fibrous ring surrounding the opening is also involved in inflammation, it wrinkles during scarring, and this further increases stenosis. To develop the so-called "laparoscopic stenosis" takes so much time that the patient is already out of childhood, and therefore this condition in childhood almost does not occur. Calcification of valves is also the greatest rarity. The degree of narrowing of the hole can be calculated with a certain percentage of probability also during life. The anatomical picture is also determined by the fact that the load from the defect initially lies on the musculature of the left atrium. While she is able to overcome the increased pressure accompanying stagnation, the blood pressure rises only in the venous part of the pulmonary circulation. Stagnation then also shifts to the arterial part, and, thus, hypertrophy of the musculature of the outflowing path of the right ventricle also occurs to overcome the additional load. Thus, the problem of maintaining the equilibrium of the circulation of the blood practically lies on a very thin-walled left atrium and on the right side of the heart, the musculature of which is much weaker than the left half. This is the reason that the insufficiency of blood circulation is much easier than in cases of insufficiency of mitral valves. Almost simultaneously with the deficiency of the left half of the heart, the right half of the heart is depleted. Reducing the strength of the heart is usually accelerated by new rheumatic dissipation.

As a result of increased blood pressure in the vessels of the small circle of blood circulation, very soon functional and morphological changes occur. Vascular spasm and hypertrophy of the walls of the vessels are equally mechanisms protecting the left half of the heart;their appearance is not closely related to the degree of distortion of the atrioventricular orifice and the time of the existence of stenosis.

Symptoms of .In the case of an unaffected myocardium, with a small stenosis, the performance of the heart for a long time is comparatively good. With pure stenosis, the face is pale, the cheeks are often slightly cyanotic, the color of the lips is on the border of cyanosis. Muscle strength is usually lowered. The apical impulse should have been due to the inactivational atrophy of the left ventricle located within the mid-succinic line, however, in view of the fact that "mitral stenosis" itself is almost never seen in childhood, the place and nature of the apical impulse are determined by the insufficiency of the valves. In cases complicated by the insufficiency of the valves, the apical impulse is also slightly elevated, visible, and palpable in the lVth, Vth, rarely in the sixth intercostal space along the mid-inclusive line or outside it. The intensive work of the right side of the heart is accompanied by pulsation of the atrial and epigastric regions.

After the onset of hypertrophy of the cardiac muscle in the compensated state, the dullness of the heart is normal or barely increased. The right edge of the heart usually reaches the right side of the sternum, the left border can be percussed along the mid-incision line or slightly out of it. Silent percussion on the left side in the 3rd intercostal space, it is possible to tap the enlarged, enlarged left atrium, which forms the edge of the heart( a symptom of Groco).If the power of the right ventricle is depleted, the stupidity of the heart can increase significantly in all directions.

The first sound phenomenon of the beginning stenosis is the clapping 1st tone. However, this symptom can be evaluated as a characteristic feature of this clinical picture only if the patient does not have an acute carditis. In these cases, in connection with the process of recovery, until then the quiet tone may suddenly increase. The next in its appearance and frequency is the phenomenon of proto-diastolic noise. If the stenosis was only relative, the diastolic murmur could disappear upon compensation. If the stenosis becomes permanent, at first soft noise becomes more and more rough, and sooner or later it is accompanied by a sensation of rustling. Noise is heard only in a limited place, above the top, and is not carried out. Significantly more often, that's why when you're young, you rarely hear presistolic murmur. This noise is caused by active atrial contraction, when it pushes blood through a significantly narrowed orifice. In order for this noise to appear above the tip and be listened to in a limited space, increasing with lying or moving patient, requires a healthy atrial musculature and a far-reaching stage of stenosis. In such cases, the noise has the character of a crescendo and continues up to the 1st tone.

In childhood, the mitral opening tone, which is pathological in adults, is very rare. In our opinion, this is due to the fact that in the childhood, the valves very rarely become so hard and Rubtsov that their opening is accompanied by such a sharp clapping sound. For the appearance of this scarring takes more time. If the tone of the opening is audible, then this tone is observed above the tip and slightly medially from it, in the second tone, well differentiated from it, and has a sharp clapping character. It is often mixed with a tone of filling, but it can be distinguished from it not only on the basis of a phonocardiogram, but also by the ear according to the nature of this tone and its distance from the second tone.

If the pressure in the pulmonary artery is very high, then the vessel expands, and the picture can be supplemented by diastolic noise of relative pulmonary insufficiency. This, however, occurs very rarely in childhood, and we ourselves observed it only in adults.

From the essence of the pathological process described above, it follows that, with the exception of cases of pure stenosis rare in childhood, a holo-systolic murmur of "mitral insufficiency" is always heard. This noise is characteristic of the sound pattern, as long as insufficiency prevails. With independent, pure stenosis, systolic murmur is also often heard, but this is a short noise characteristic of "functional noise".

On a phonocardiogram, the presystolic crescendo noise starts simultaneously with the descending segment of the P wave on the ECG, continues to the Ith tone and often merges with it. This noise is caused by accelerated filling of the ventricle due to active contraction of the musculature of the atrium. With weakened atrial work( if the atrium is overextended, with flicker and flutter of the atria, etc.), this noise disappears. In the case of partial or complete atrioventricular blockade, this noise is separated from the 1st tone. Proto-diastolic noise initially consists of high frequency oscillations, and later from high and low frequency oscillations. It begins at the same time as the III-th tone, continues with decreasing intensity as much as possible to the middle of the diastole. The third tone means the beginning of the rapid filling that causes this noise. With the slowing down of rapid filling, the noise disappears. The opening of the mitral valves, as mentioned above, is rare in childhood. If it does occur, it occurs either in cases of pure stenosis, or with old heart defects by the end of puberty. On our own phonocardiographic material of 58 cases of "mitral stenosis" this phenomenon occurred only in 7 cases( 12%).Thus, its diagnostic value in childhood is by no means as great as that of adults. If it is seen on a phonocardiogram, this usually represents a group of vibrations - a mixture of high and low tones - which occurs after II-th tone in 0,08-0,10 seconds. With a very small deviation, this tone of opening coincides with the point "O" of the vertex curve and with the "y" tooth of the venous curve.

Amplitude II-th tone at the site of listening to the pulmonary artery is much larger than the amplitude of the 1st tone. Often there is a doubling of the second tone.

With this heart disease, there are no direct electrocardiographic data typical for it. Teeth P in the 1st and 2nd leads from the extremities are enlarged, have two vertices and show the slowing down of the impulses within the excessively dilated atria( atrial asynchrony).The duration of PQ in the I-th and II-th lead in such cases is the same. The vector R is usually deflected to the right, but the R tooth never becomes negative. With concomitant mitral valve insufficiency or aortic insufficiency, the vector R can remain in the middle position.

With sagittal x-ray examination, the magnitude of the cardiac shadow with pure stenosis is normal or even less. If the transverse diameter of the heart is increased, this is usually caused by the expansion of the right ventricle. The shadow of the conus pulmonalis and the pulmonary artery protrudes forward. The shadow of the appendage of the dilated left atrium, merging with the above two arcs, fills the cardiac cavity. With a significant expansion of the left atrium, the shadow of the appendage appears on the right side next to the shadow of the right atrium. In such cases, the doubled right lower arc appears. With the right forward oblique position, the upper part of the Holzknecht space narrows or is completely closed by the dilated left atrium. On the esophagus, it causes an indentation and pushes it back in the form of a convex arc. With the left anterior oblique position - and even more pronounced in the lateral position - the enlargement of the left atrium is seen indirectly, it narrows the aortic window below. A heavily dilated left atrium can lift the left main bronchus. If valve failure is predominant, the X-ray pattern changes accordingly. The gyulose pattern is dense, the pulmonary pattern is pronounced. The gilius adopts the pulsation of the left atrium, and a superficial examination may give the impression of a "gigantic dance".

From the point of view of differential diagnosis, almost without exception, the relative narrowing of the hole presents a difficulty. The diastolic murmur heard above the apex of the heart is caused, in addition to the constriction of the left venous aperture, only by the insufficiency of the aortic valves, but its character and the point of maximum audibility are so different from those in "mitral stenosis" that it facilitates the setting of a differential diagnosis.

Heart Disease Value .The constriction of the left venous aperture almost always reduces the capacity of the heart to a greater or lesser extent, although with a healthy heart muscle a child can not appear for a long time. Increased pressure, resulting from insufficient emptying of the left atrium, is overcome by hypertrophy of the musculature of the atrium. If the increased pressure extends to the small circle of the circulation, then a significant part of the load from the defect falls on the right side of the heart. People with reduced performance often complain of shortness of breath and fatigue, appearing during games or sports activities. They usually learn badly, indifferent and inattentive. These people are prone to respiratory infections, they are easily attacked by bronchitis, bronchiolitis and bronchopneumonia. Over time, narrowing of the opening can progress and without new inflammation as a result of the scarring of scar tissue. If the stenosis reaches a significant degree, then increasing pressure in a small circle of circulation and then hypertension in the same place put the right half of the heart in front of such an increased load that it can not perform for a long time. Previously, the fate of such patients was predetermined, but recently the operative resolution of the stenosis of the hole in the older age greatly facilitates the fate of such patients. Very quickly worsens the condition of children born with a narrowing of the left venous aperture. Because of the frequent pneumonia and because of the soon-occurring insufficiency of the right heart without surgery, their life is short.

Normally, insufficient attention is paid to the insufficiency of the tricuspid valve that joins the stenosis of the left venous aperture. In our experience, the relative insufficiency of the tricuspid valve is often attached to the stenosis of the left venous aperture and in childhood, or the relative insufficiency of the tricuspid valve that results from the expansion of the right half of the heart, which considerably worsens the prognosis due to poor compensatory possibilities of the already overloaded right heart.

In the textbooks of therapy and cardiology, it is unanimously asserted that in approximately 50% of cases, fibrillation or atrial flutter and absolute arrhythmia join the stenosis of the left venous aperture. In our experience in childhood, the disorder of the formation and carrying out of impulses is rare, but if it is still there, then the prognosis is very bad, because it always comes when the heart, which has already reached the limit of its efficiency, undergoes rheumatic dissipation. Such patients in a short time all without exception are killed.

Such an often mentioned among the complications of "mitral stenosis" of the atrial thrombus and ensuing from this embolism in the great circle of blood circulation, are rare in childhood.

About the therapy of acquired heart defects in detail in the article Treatment of children with heart disease

Conclusion .In childhood, the relative narrowing of the left venous aperture is not a rare phenomenon. It often has two causes: acute left ventricular dilatation and aortic valve failure. Due to the acute expansion of the left ventricular musculature, the ventricle cavity suddenly increases. The fibrous ring of the opening very slowly or does not follow the extension at all, and thus a relative stenosis of the opening arises. Most often this is the case with acute bacterial carditis accompanied by rapid expansion. Diastolic noise disappears with the termination of expansion. Literary data and our own experience warn us that it is impossible to consider without criticism the noise coming during the carditis of relative stenosis, the final one. However, these symptoms can be assessed only if they are heard even after 1 / 2-1 year after clinical recovery from inflammation, after cessation of expansion. When the aortic valves are inadequate, the blood flowing back with diastole raises the anterior mitral valve, as if pushing it into the hole and thus narrowing the opening of the hole. The resulting diastolic noise is called the Austin-Flint noise. In many cases it is impossible to decide whether the noise is a symptom of a true or relative stenosis of the orifice. With a compensated condition, the normal value of the left atrium indicates a relative stenosis, but this is not yet proof.

Read more Insufficient aortic valves
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