Atrioventricular canal malformation

Introduction to atrioventricular tube malformation The atrioventricular tube defect has been called endocardial pad defect, the first hole type defect, the atrioventricular common tract, or the primary hole defect is a series of congenital heart malformations formed by the first septum and endocardial dysplasia. The lesions are partially missing at the atrioventricular ring, the lower atrium, and the ventricular septal tissue, and may be associated with varying degrees of atrioventricular valve malformation. The atrioventricular tube malformation is rare, accounting for only 5% of all types of atrial septal defect. basic knowledge The proportion of illness: the incidence rate is about 0.03% - 0.08% Susceptible people: no special people Mode of infection: non-infectious Complications: mitral regurgitation tricuspid regurgitation

The cause of atrioventricular tube malformation

The disease is a congenital disease, which is formed by the development of primary atrial septal dysplasia or excessive absorption during embryonic development. It can be divided into partial type of atrioventricular tube malformation and complete type of atrioventricular tube malformation. The flow to the right is large, the symptoms appear early, and the condition is heavier.

Atrioventricular tube malformation prevention

Patients with atrioventricular tube malformation who have not undergone surgery, the development of the disease varies depending on the type and function of the lesion, and the first type of defect and the mitral valve have only mild reflux. With other congenital heart vascular malformations, the natural progression of the disease course is similar to that of the larger second-port atrial septal defect. Nearly 10 to 15% of cases have pulmonary vascular obstruction caused by pulmonary hypertension in the 20-40 age group. Lesion.

Partial type of atrioventricular tube malformation mitral regurgitation in moderate to above, left to right sub-flow, pulmonary hypertension, at least 20% of cases in the infants and young children showed obvious symptoms, and died before the age of 10.

Complete type of atrioventricular tube malformation is rare, and there is not enough data on the natural progression of the disease. It is estimated that about 80% of those who have not undergone surgery will die of pulmonary vascular obstructive disease and congestive heart failure at the age of 2, therefore, each type of room Cases of esophageal malformation should be treated with surgery in the early years, but if the resistance of the lung circulation exceeds 70% of the resistance of the systemic circulation, surgery should be contraindicated.

Atrioventricular tube malformation complications Complications mitral regurgitation tricuspid regurgitation

In addition to the lung circulation resistance exceeding 70% of the systemic resistance, it is contraindicated for surgery. All types of atrioventricular tube malformations should be performed early. Complications include:

1. Residual atrial or ventricular septal defect.

2, abnormal cardiac conduction (arrhythmia and complete heart block).

3, mitral regurgitation.

4, tricuspid regurgitation.

Symptoms of atrioventricular tube malformation Common symptoms Atrial fibrillation in the atria, ventricular ventricular septal defect, cardiac tremor, tremor, enlarged heart, aortic dislocation, airway, patent ductus arteriosus, right heart failure

(1) Clinical manifestations

The clinical manifestations of atrioventricular tube malformation vary according to the type of lesion, the size of left-to-right sub-flow, the severity of atrioventricular valve regurgitation and the increase of pulmonary vascular resistance. The clinical manifestations of simple atrial atrial septal defect Generally, the atrial septal defect is similar. Most patients may not present clinical symptoms in the early years after birth. When they grow up, pulmonary vascular obstructive lesions can cause palpitations, shortness of breath, decreased exercise tolerance, respiratory infection and right heart failure. symptom.

Partial type of atrioventricular common cases have poor physical growth and early pulmonary hypertension, and the aforementioned clinical symptoms and heart failure can be presented in the early years and continue to increase.

Complete-type atrioventricular co-channel cases can present pulmonary hypertension within 1 year or even 1 month after birth, heart failure and progressive aggravation, rapid breathing, poor peripheral circulation, increased heart and purpura, often in early death. About half of the patients are accompanied by congenital dementia.

(2) Physical examination

Most of the sick children have slow growth, the anterior thoracic full bulge, strong apex beats, and enlarged heart sound zone. The chest signs of the first atrial atrial septal defect are similar to those of the second atrial septal defect, and there are atrioventricular valve lobes. In the pre-cardiac region of the complete atrioventricular co-channel, a rough full-systolic murmur can be heard. The apical region is the loudest and can be tremor. The second tone of the pulmonary valve in the pulmonary hypertension case is strengthened, fixed and split, and the lower left side of the sternum Diastolic drum-like murmurs may be heard in the apical area, and the liver is swollen in heart failure cases, sometimes with purpura.

Examination of atrioventricular tube malformation

There are several methods of examination that can be used for this disease:

(1) Chest X-ray examination: the chest X-ray findings of the first atrial atrial septal defect are similar to those of the second atrial septal defect with large defect, and there are partial and complete compartments of atrioventricular valve regurgitation. In the common cases, the heart was obviously enlarged, the left ventricle, the right ventricle, and the right atrium were enlarged. The pulmonary blood vessels were significantly congested, the pulsation was enhanced, and the pulmonary circulation resistance was significantly increased. The pulmonary vascular shadows in the hilar region were thickened and the blood vessels around the lung field were thickened. The shadows are scarce.

(2) Electrocardiogram examination: prolonged PR interval, significant hypertrophy of right ventricle or incomplete right bundle branch block, left ventricle also hypertrophy, left axis of electric axis, QRS ring of frontal heart vector diagram is reversed. The main part of the QRS ring moves upwards to the left or even to the right, and the average electric axis is between -30° and -140°. Some authors point out that the QRS ring of the frontal heart vector diagram of some type of atrioventricular common cases is reversed. In the left direction, the horizontal surface QRS reverses the needle to the left to the rear; the full-type atrioventricular common road has the frontal surface QRS in the reverse needle running direction to the right, and the horizontal surface QRS reverses the needle running forward to the right.

(3) Echocardiography: the right atrium, the right atrium and the pulmonary artery have an increased inner diameter. The movement of the ventricular septum is subordinate to the contraction of the right ventricle. During the ventricular ejection, the ventricular septum presents a forward movement, that is, contradictory movement, and the section ultrasound Cardiogram examination showed the lower part of the interatrial septum, the interventricular septum, the mitral anterior leaflet and the tricuspid valve leaflet. Under normal circumstances, the cross formed by the interconnection in the central area disappeared, and the echo of the lower part of the interatrial septum and the upper part of the interventricular septum Interrupted, the four heart chambers communicate with each other, the mitral valve advances, the anterior leaflet approaches the tricuspid valve leaflet during systole and approaches the ventricular septum during diastole, the mitral valve diastolic phase is suspended, and the left ventricle flows out. The narrowing of the tract, after the ultrasound contrast agent is injected into the peripheral vein, the left ventricular systolic pressure is higher than the right ventricle, and the diastolic right ventricular pressure is slightly higher than the left ventricle. The contrast agent can be seen on the upper part of the ventricular septum. flow.

(4) right heart catheterization: the catheter can enter the left atrium from the right atrium, or directly into the left ventricle from the right atrium. There is a left to right shunt at the level of the atria and ventricle. The blood oxygen content in the right atrium is higher than that in the vena cava. Oxygen content may be further elevated than the right atrium. Patients with pulmonary hypertension may show right to left shunt and pulmonary vascular resistance, and right atrial pressure waveform with mitral valvular fracture may show V wave rise due to atrioventricular valve insufficiency. high.

(5) Selective left ventriculography can show that contrast agent flows into the right ventricle and/or right atrium through the atrial and ventricular septal defect; the left ventricle is resected through the atrioventricular valve and can show the size and size of the cardiac septal defect. In the case of ventricular malformation, the contrast agent injected into the left ventricle in some cases of atrioventricular common tract flows back into the left atrium, and then enters the right atrium, right ventricle and pulmonary artery in sequence; the complete type of atrioventricular co-channel case contrast agent left ventricle Back into the left and right atrium, also from the left ventricle through the ventricular septal defect directly into the right ventricle, even if the left, right atrium and right ventricle, pulmonary artery development at the same time, the atrioventricular co-channel case moved to the apex due to the position of the atrioventricular valve And the ventricular septal defect, the left ventricular outflow tract is narrow and long, and the gooseneck sign appears on the left anterior left ventricle X-ray. Therefore, selective left ventricular angiography can identify the first and second atrial septal defect. And it is also valuable for identifying partial and complete room sharing.

(6) Atrioventricular tube malformation with complete ventricular septum and no pulmonary hypertension, such as decreased arterial blood oxygen saturation, should be considered as a single atrial malformation.

Diagnosis and diagnosis of atrioventricular tube malformation

Diagnosis of atrioventricular tube malformations should be identified in the following diseases:

(1) Secondary atrial septal defect:

The following points can be identified:

1 Secondary atrial septal defect in the pulmonary valve area and systolic murmur, without murmur of the mitral valve, tricuspid regurgitation.

2 secondary hole type atrial septal defect ECG axis right deviation, incomplete right bundle branch block, right atrium, right ventricular enlargement, atrioventricular tube malformation with left axis deviation, left anterior bundle branch block.

3 echocardiography and cardiovascular angiography can show ventricular septal defect, crisscross split, atrioventricular valve malformation.

(B) ventricular septal defect:

Complete atrioventricular tube malformations have different sizes of ventricular septal defect, similar to giant ventricular septal defect, but the apical murmur of mitral regurgitation is not heard in the apical region. The differential diagnosis depends on echocardiography and angiography. an examination.

(C) simple pulmonary artery stenosis:

Simple pulmonary artery stenosis and complete atrioventricular tube malformation can detect jet murmur in the second intercostal space of the left sternal border, but the former has mild clinical symptoms, the second sound of pulmonary valve is weakened or disappeared, and there is no mitral and tricuspid valve. Closed incomplete murmur, X-ray chest radiograph showed pulmonary less blood, echocardiography can be identified.

(4) Other congenital heart diseases:

Such as clinical appearance of purpura, may be misdiagnosed as tetralogy of Fallot, transposition of the great arteries, tricuspid atresia, venous venous drainage, etc., but echocardiography, cardiac catheterization and cardiovascular angiography can be identified.

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