single atrium
Introduction
Single heart introduction Single atrial is a rare congenital heart disease caused by the absence of the first and second compartments of the interventricular septum during embryonic development. The traces of the room are also not present, and the compartment is complete, so it is also called the two-chamber three-chamber heart or the single-atrial three-chamber heart. Single atrium can exist alone, but often combined with the left superior vena cava and right heart, left heart or abdominal visceral transposition malformation, especially the anterior mitral lobes, and even the atrioventricular tube malformation. basic knowledge The proportion of illness: this disease is rare, the incidence rate is about 0.0001% Susceptible people: no specific population Mode of infection: non-infectious Complications: congestive heart failure, cerebral embolism
Cause
Single atrial cause
Cause:
The disease is a congenital disease, due to the development of the single-chamber heart embryo, the first compartment and the second compartment of the interatrial septum are not developed, resulting in the formation of a common atrium, so it is also called the two-chamber three-chamber heart or single-atrial Three cavity heart.
Pathological changes:
The venous and venous blood from the vena cava and the pulmonary veins are mixed in a single atrium. Because the right ventricular filling resistance is small, most of the blood enters the left ventricle, and the pulmonary veins return to the atrial blood flow. Only a part of the mitral valve enters the left ventricle. Systemic circulation, so purpura can appear clinically. On both sides of the atrium, the oxygen saturation in the ventricle, aorta and pulmonary artery is almost the same. Single-atrial venous venous drainage is common, such as the left superior vena cava into the coronary sinus or The left side of the common atrium, followed by the inferior vena cava through the azygous or semi-singular vein drainage and the hepatic vein directly into the right side of the common atrium, forming a mixed blood in the atria.
Prevention
Single atrial prevention
The disease is a congenital disease, so there is no effective preventive measure, but for children with a clear diagnosis, as long as serious pulmonary vascular obstructive disease has not occurred, early surgery should be sought.
Complication
Single atrial complication Complications, congestive heart failure, cerebral embolism
Often complicated by bronchial pneumonia, congestive heart failure, cerebral embolism, pulmonary edema and subacute bacterial endocarditis, postoperative complications often occur, mainly in the following cases:
1. The occluder is detached:
For children with occlusion surgery, the complication of occlusion device can be complicated. The occluder is often detached due to the choice of occluder too small or improper operation. It can also be caused by the ASD edge being less than 4 mm or the edge being thin. After the closure is fixed, the fixation is not strong. The occluder is often removed by emergency surgery. It is also reported that the trap can be used. The key to prevent this complication is to choose the occluder according to the size of the ASD. The TEE is more accurate before surgery. Measure the diameter and edge of the ASD and select the occluder with reference to the TEE measurement.
2. Residual shunt:
Residual shunt after interventional treatment of ASD is usually related to the choice of occluder. Choosing a smaller occluder is the most common cause of residual shunt after surgery. Micro-displacement of occluder after surgery is also a cause of residual shunt after surgery. A small amount of residual shunt has little effect on hemodynamics and can be followed up. If the residual fractional flow is large, surgical removal of the occluder and closure of ASD should be performed.
3, arrhythmia:
III degree AVB is a common serious complication of ASD occlusion. It can occur in intraoperative and postoperative cases. It is more common in larger ASD. Because of the large diameter occluder, the edge can squeeze the atrioventricular node area, resulting in serious Atrioventricular block, once AVB occurs during surgery, the occluder should be recovered, temporary cardiac pacing should be performed if necessary, sinus bradycardia can also be seen in occlusion, and the occlusion device is placed in the posterior septum Pulling causes vagus reflexes, often without special treatment, slow heart rate can be treated with atropine.
4, embolic complications:
Coronary air embolism is common, which is characterized by transient ST-segment elevation or bradycardia in the electrocardiogram. The occurrence is related to the operation. Because the atrial pressure is low, the air can enter the left atrium after the delivery sheath is delivered to the left atrium. The occluder should be pushed at the end of the delivery sheath when the blood flows out, followed by the cerebral embolism, which can lead to serious consequences such as hemiplegia. The occurrence of cerebral embolism is related to the local secondary thrombosis after the occluder is placed. Anticoagulation and antiplatelet therapy are the key to preventing postoperative embolic complications.
5, pericardial filling:
This disease is the most serious complication of ASD occlusion, and it can lead to death if not treated in time. One case of pericardial tamponade occurred in this group, which occurred in the early stage of interventional therapy, due to the injury of the left atrial appendage due to guide wire or catheter injury. The operator is not properly operated and has insufficient experience. During the operation and after surgery, the condition should be closely observed. Once the pericardial effusion is found, the pericardial puncture should be performed as soon as possible before the pericardial tamponade, so as to avoid serious consequences.
6, phlebitis:
Found in pediatric patients, ASD diameter is larger, intraoperative selection of larger delivery sheath caused by iliac vein injury.
7, the aorta - right atrium:
This disease is one of the serious complications in the late stage after ASD closure. The selected occluder is too large, and the condition of the anterior superior margin near the defect is poor, resulting in mechanical friction of the aortic root at the edge of the occluder. It has been reported that the incidence of late complications of cardiac injury after ASD closure is 0.06% to 0.10%, mainly aortic-right atrial fistula, aorta-left atrial fistula and cardiac tamponade. Should be treated surgically.
8, bleeding at the puncture site:
Due to the application of heparin during surgery, postoperative child agitation may cause bleeding at the puncture site. The amount of intraoperative blood loss should be inquired in detail, and the vital signs and puncture points of the child should be closely observed. Resting in bed for 24 hours, keeping the puncture limb braked for 6 to 8 hours. The anesthesia will be awake when the child appears to be awake, according to the doctor's advice to give 10% chloral hydrate. 0ml / kg enema or midazolam 0. 3 ~ 0. 5mg / kg intravenous bolus, explain to parents and older children before surgery The importance of bed rest after surgery and the cooperation of patients are also important for preventing bleeding at the postoperative puncture site.
9, infection:
After routine application of antibiotics for 3 days, pay attention to the changes in body temperature, and measure the body temperature once every 4 hours. If the fever or fever lasts longer than 3 days, report to the doctor and strengthen the antibiotic treatment.
Symptom
Single atrial symptoms common symptoms shortness of breath purple cicada (toe) heart failure systolic murmur
Symptoms and signs are similar to large atrial septal defect and atrioventricular tube malformation. Frequent crying and irritability, cyanosis, early heart failure, gradual cyanosis and clubbing, toe, jet murmur in the pulmonary valve area, 2nd The sound is in a fixed division, and the apical region has a systolic murmur of mitral regurgitation.
Examine
Single atrium check
The following examination methods are conducive to the diagnosis of this disease:
(1) Chest X-ray: It shows an increase in pulmonary vascular shadows and enlarged heart shadow. The right atrium and right ventricle are enlarged, and the pulmonary artery is bulged.
(2) ECG examination: the left axis of the axis, often atrioventricular junction rhythm, roughly similar to the atrioventricular tube malformation.
(3) Cut surface echocardiography: between the left and right atrium, the echo of the interatrial echo disappears, and the four-chamber view is normal, with a cross formed by the interatrial septum, interventricular septum, mitral valve, and tricuspid valve. The echo reflection changes to a T-shaped echo reflection.
(4) right heart catheterization: the catheter is easy to enter the left atrium from the right atrium or the catheter path is similar to the atrioventricular tube malformation. In fact, the single atrium is mixed blood, so the blood oxygen saturation of the atrium, ventricle and two great arteries is similar. .
(5) Selective atrial angiography: single atrium can be displayed, left ventricular angiography can show mitral regurgitation.
Diagnosis
Single atrial diagnosis
Single atrial need to be differentiated from ventricular septal defect, complete pulmonary venous return, complete aortic dislocation, tricuspid atresia and complete atrioventricular canal malformation, single atrial clinical symptoms and signs similar to large atrial septal defect or atrioventricular tube malformation, However, the symptoms appear early and heavy, there is purpura but the pulmonary blood flow increases, the atrial level has a large number of left to right shunt but no evidence of obvious pulmonary hypertension. From the pathological point of view, the ventricular septal defect has some interatrial residual, room Less interval defects, which is beneficial to the differential diagnosis of the two, other diseases such as complete pulmonary venous return, complete aortic dislocation, tricuspid atresia and complete atrioventricular tube malformation can also be checked by other auxiliary examination methods Out.
