Single ventricle

ingle ventricle. It is a congenital heart disease characterized by the existence of a dominant ventricular cavity, endowed with an entrance sinus and a well-developed trabeculated portion with which the two atria fully connect (double entry, common atrioventricular valve or atresia of an atrioventricular valve) or dominant ( more than 50% crowding of one of the atrioventricular valves).

Summary

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  • 1 Pathological anatomy
  • 2 Hemodynamics
  • 3 Clinical signs
  • 4 Diagnosis
  • 5 Forecast
  • 6 Treatment
  • 7 Sources

Pathological anatomy

In most cases with a single ventricle, the entire interventricular septum is missing, and the tricuspid valve and mitral valve open within the single ventricle. Sometimes a rudimentary girdle or ridge divides the two inlet streams, in addition, there is often a concomitant transposition of the great vessels. Atrial septal defect is also common and at least a quarter of patients have pulmonary stenosis .

Hemodynamics

The common ventricle receives pulmonary and venous blood from the general circulation. Unless there is stenosis, there is excessive flow to the lungs, and heart failure may develop early. If severe pulmonary stenosis is present, cyanosis occurs during the first days of life.

Clinical signs

Signs of congenital heart disease appear soon after birth in most children with a single ventricle. These signs vary in each case: the intensity of cyanosis (which may even be absent) is variable, although it is often greater in children with pulmonary stenosis. Frequently audible systolic murmurs are heard in the precordial region, which do not have a typical location. A systolic catarrhal thrill is felt less frequently in the newborn than in older children with this abnormality.

Cardiomegaly is absent or not noticeable early in life, and the cardiac contour varies. If there is a concomitant pulmonary stenosis, you can acquire the characters from the Tetralogy of Fallot . It can also simulate the contour observed in the transposition of the great vessels, because this anomaly is frequently combined with the single ventricle. In both cases, the contour is less characteristic in the newborn than in older children.

There is no typical EKG trace: Axial deviation to the left or right may be seen, with ventricular hypertrophy on the left or right side. In a large study of left axillary deviation in patients with congenital heart disease, Brink and Nelly found it in 20 of 91 patients with a single ventricle. These authors concluded that the single ventricle is a frequent cause of left axial deviation in patients with cyanotic congenital heart disease, however, this fact is not explained when it manifests during the neonatal period, during which it can be recorded. a uniform path in all precordial leads. The existence of a single ventricle in the presence of said tracing will be suspected, provided it is not due to technical artifacts.

Diagnosis

Diagnosis of a single ventricle is greatly hindered by the variety of clinical symptoms and radiographic and electrocardiographic signs. Children with a single ventricle and severe pulmonary stenosis manifest severe cyanosis early in life, as do children with tricuspid atresia and the effects of Tetralogy of severe Fallot. If cardiomegaly with early heart failure is found in addition to cyanosis, the possibility of transposition of the great vessels, pulmonary atresia, or severe pulmonary stenosis will also be considered in the differential diagnosis.

Children with a single ventricle, doubtful or absent cyanosis, and a sonic systolic murmur may present a symptom similar to that of the group with a left-to-right shunt, and especially that of patients with a ventricular septal defect and patent ductus arteriosus .

From all the above it is clear that the clinical signs produced by the single ventricle can simulate all degrees of congenital cardiac defects. Other tests are almost always needed; Angiocardiography will reveal a large single ventricle, and transposition of the great vessels and cardiac catheterization will verify a higher oxygen concentration in the right ventricle than in the right atrium and a ventricular pressure similar to that of the greater circulation.

Forecast

As can be assumed, the prognosis varies as much as the clinical picture. Nadas states that children with a single ventricle can die during the first week of life if there is little resistance and pulmonary overload or if the pulmonary stenosis is of the highest degree. The prognosis is much better in patients with benign degrees of pulmonary stenosis.

Treatment

Using the Blalock-Taussig anastomosis, palliative treatment can be performed when there is pulmonary stenosis. Muller and Dammann recommended the production of a benign pulmonary stenosis. In older children it is now possible to create a prosthetic septum (Shigeru et al .; Edie et al.).

 

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