single ventricle
Introduction
Single ventricle introduction A single ventricle (common ventricle) or a univentricular heart is a rare congenital malformation. Its incidence is about 1:6500 in live babies, about 1.5% of congenital heart disease, and the ventricles receive blood from both the tricuspid and mitral valves or the common atrioventricular valve. basic knowledge The proportion of illness: 0.005% Susceptible people: no specific population Mode of infection: non-infectious complication:
Cause
Single ventricular cause
Cause:
From the embryonic basis, the formation of a single ventricle is due to the failure of the atrioventricular canal to correctly align with the developing ventricle, so that both atrioventricular valves are facing one ventricle, often complicated by pulmonary valvular obstruction, then Due to the deviation of the funnel spacing.
Pathological changes:
The single ventricle itself can be divided into many subtypes. Van Praagh et al. classify them into four types according to the morphology of the ventricle body: the type A, the morphological left ventricle with the original outflow tract including the right ventricular funnel; Morphological right ventricle without left ventricular sinus (the left ventricular remnant can be a non-functional fissure or pocket); type C, ventricle including the left and right ventricles, no interventricular septum or only There are remnants; D type, the ventricle does not have the characteristics of right ventricle or left ventricle (no right ventricle and left ventricular sinus), these four types can be further divided according to their connection with the aorta and the location of the aorta space Is I (normal), II (right) or III (left), according to Van Praagh, type A is 78%, type B is 5%, type C is 7%, type D is 10%; and large blood vessels In the case of translocation, the number of right or left ankles was similar, with 42% and 43% respectively, and 15% of the aorta was normally aligned.
Prevention
Single ventricle prevention
Most single-ventricular patients have obvious congenital heart disease in early years, such as purpura, tachycardia or slow weight gain, which attracts attention in early neonates or infants. For patients with more pulmonary blood, there are often no early cases. The natural lifespan of single-ventricular patients was found to be short without treatment. According to the Toronto Children's Hospital, 117 (64%) of the 182 deaths, 50% died within 1 month after birth, and 74% died. 6 months, Moodie et al analyzed 83 patients who had not undergone surgery and most of them had passed the infancy. From the date of diagnosis, 50% of type A patients died on average within 14 years, and type C patients had a worse prognosis, 50%. After 4 years of death, the presence or absence of pulmonary stenosis does not affect the length of life. The cause of death is mainly congestive heart failure and arrhythmia, or sudden death due to unknown causes.
Complication
Single ventricular complications Complication
Single ventricle combined with other congenital heart malformations, pulmonary stenosis and atrial septal defect are the most common, seen in 51% and 27% of patients, respectively; can also be associated with coronary artery malformations; conduction system position is abnormal and variable, in one out of the mouth In patients with inconsistent relationship between the room-chamber and ventricle-aorta (left iliac crest), the atrioventricular node is abnormally anterior. In patients without a ventricle, the position of the atrioventricular node is uncertain, and can be posterior and lateral. Position or anterior position; when the outlet chamber is left to the front position, the total conduction beam surrounds the front of the pulmonary valve outflow tract, close to the attachment of the pulmonary valve; if the outlet chamber is in the right and anterior position, the conduction beam is located in the pulmonary valve The lower rear of the ring; in the absence of the oral cavity, the conductive beam is located behind the ventricular body.
Symptom
Single ventricular symptoms common symptoms heart failure weight loss systolic murmur purpura finger (toe) tachycardia arrhythmia
Most single-ventricular patients have obvious congenital heart disease in early years, such as purpura, tachycardia or slow weight gain, which attracts attention in early neonates or infants. For patients with more pulmonary blood, there are often no early cases. The natural lifespan of single-ventricular patients was found to be short without treatment. According to the Toronto Children's Hospital, 117 (64%) of the 182 deaths, 50% died within 1 month after birth, and 74% died. 6 months, Moodie et al analyzed 83 patients who had not undergone surgery and most of them had passed the infancy. From the date of diagnosis, 50% of type A patients died on average within 14 years, and type C patients had a worse prognosis, 50%. After 4 years of death, the presence or absence of pulmonary stenosis does not affect the length of life. The cause of death is mainly congestive heart failure and arrhythmia, or sudden death due to unknown causes.
Examine
Single ventricle examination
Physical examination
Pulmonary blood flow reduction can be seen in purpura and clubbing (toe), abnormal increase in pulmonary blood flow in patients with chronic congestive heart failure, poor growth, weight loss, congestive heart failure or right atrioventricular stenosis without atrial septal defect When the jugular vein is full or violent, such as the right atrioventricular valve regurgitation is severe, the jugular vein and liver will have systolic pulsation.
At the time of visual examination and percussion, the heart beats are diffused. Because many patients have their aorta relatively front, the closure of the aortic valve can be detected at the left sternal border of the sternum.
The first heart sound can be enhanced during auscultation, and the second heart sound is stronger and single. Most patients can hear the loud systolic murmur. The patient is from pulmonary stenosis or subaortic stenosis. The patient with increased pulmonary blood flow is at the apex of the heart. The area can hear the diastolic murmur caused by the relative stenosis of the left atrioventricular valve.
ECG check:
The sub- ventricular subtypes are not the same, but most patients have ventricular hypertrophy.
Chest X-ray examination:
Most patients have enlarged heart shadows. The increase or decrease of pulmonary blood depends on the presence or absence of pulmonary stenosis. The enlargement of the left atrium is seen in the increase of pulmonary blood or the atresia of the atrioventricular valve. In other respects, the pathological anatomy of each subtype is considered. Different.
Cardiac catheterization and cardiovascular angiography: between the two-dimensional echocardiography and color Doppler diagnostic techniques, cardiac catheterization and cardiovascular angiography are needed to confirm the diagnosis of single ventricles and their types, as well as to merge the deformities. The purpose should include:
1 type of single ventricle;
2 the presence and location of the chamber at the exit;
3 the spatial location of the pulmonary artery of the aorta and the relationship between the chamber and the chamber;
4 presence or absence of pulmonary artery or aortic blood flow obstruction;
The number, location, functional status of the 5 compartment flaps, as well as their deviation and riding conditions;
6 pulmonary artery pressure and resistance;
7 ventricular function (body blood fraction and end-diastolic pressure);
8 pulmonary artery thickness, distribution or distortion caused by previous ring bundle surgery;
9 With the deformity, although the venous blood of the systemic circulation and pulmonary circulation is mixed in a single ventricle, due to the different blood flow in the heart chamber, the pulmonary artery and the aortic oxygen saturation cannot be considered to be exactly the same, so the lung circulation and systemic circulation are accurately calculated. For resistance, the oxygen saturation and pressure of the two arteries must be measured separately.
Echocardiography:
Two-dimensional ultrasound imaging has basically replaced invasive cardiac catheterization, and has been observed and analyzed in many aspects of single-ventricular patients, such as basic anatomy of the heart, relationship of aorta, accompanying cardiac malformation, pulmonary stenosis or ventricle exit. The situation of the Department, etc., two-dimensional echocardiography can be observed and understood. The new Doppler technique can also quantitatively measure the degree of pulmonary stenosis, ventricular output obstruction and atrioventricular valve insufficiency. Echocardiography To understand the morphology of the atrioventricular valve, deviation and riding are better than cardiovascular angiography.
Diagnosis
Single ventricle diagnosis
diagnosis:
Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.
Differential diagnosis:
Single-ventricular diagnosis is not difficult, and preoperative pathological anatomy is not easy. Therefore, in the differential diagnosis, the focus is on the identification of different types of single ventricles. Anderson divides the single ventricle into three types:
1 left ventricle type: the main shape of the left ventricle, the right ventricle is only a small residual cavity.
2 right ventricular type: mainly in the shape of the right ventricle, the left ventricle is only a residual cavity, clinically rare.
3 intermediate type: left and right ventricle morphology coexist and the interventricular septum is absent.
According to whether the atrium is orthotopic, whether there is aortic dislocation, pulmonary artery stenosis and other subtypes, single ventricle often combined with other intracardiac malformations, clinically, the left ventricular type single ventricle is the most common, accounting for about 80%, left ventricular type single ventricle Often accompanied by a dislocation of the left aorta, the right atrioventricular valve is a mitral valve, the left atrioventricular valve is a tricuspid valve, and some patients have a column of meat between the left and right atrioventricular valves, such as the pulmonary artery originating from the right side. In front of the atrioventricular valve, its anatomical structure is most conducive to the separation surgery. The left ventricular type single ventricle is accompanied by a dislocation of the right aorta, often with pulmonary stenosis, and it is not easy to do the separation surgery.
