What Causes Hypoplastic Left Heart Syndrome?

This entry was reviewed by Zheng Chunhua (Chief Physician), Department of Pediatric Cardiology, Affiliated Hospital of Capital Institute of Pediatrics

Basic Information

English name: hypoplastic left heart syndrome: HLHS
Visiting department: Pediatrics
Multiple groups: Newborn
Common locations: Aorta, aortic valve, left ventricle, mitral valve

Common causes: Congenital cardiovascular malformations are related to multiple factors: heredity, genetic mutation, radiation, and viral infection.
Common symptoms: Symptoms of cyanosis, shortness of breath or dyspnea, and heart failure can develop within hours of birth

Causes of left heart dysplasia

Left heart dysplasia syndrome is a rare and complicated congenital cardiovascular malformation. This disease is related to multiple factors, such as heredity, genetic mutation, radiation, and viral infection.

Clinical manifestations of left heart dysplasia

The child may be a normal term infant, but progressive cyanosis, shortness of breath or dyspnea, and heart failure can occur within a few hours after birth, with blood pressure of the limbs below 40mmHg. There was no specific murmur on auscultation of the heart. Pulmonary valve area is hypertonic and monotonous. Pulse is weak. Accompanied by oliguria, acidosis, hypoglycemia, hypoxemia, and shock. If the atrial septal defect flow is large, cyanosis may not be obvious, and hypoxemia is mild.

Left Heart Dysplasia Examination

Chest radiograph

The right atrium and right ventricle were enlarged, the heart shadow was spherical, pulmonary congestion, and pulmonary edema appeared.

2. ECG examination

The P wave is sharp, the electric axis is deviated to the right and the right ventricle is hypertrophic.

3. Echocardiography

The right atrium and right ventricle are enlarged, and the small wall of the left ventricle is thick, and the mitral and aortic valves are underdeveloped, or the mitral and aortic valves are blocked, and the ascending aorta and arch are small. Pulmonary arteries are widened, large arterial ducts are not closed, and ventricular septal and atrial septal defects may be present; tricuspid regurgitation may be present.

4. Right heart catheterization

Can show atrial horizontal shunt and confirm the presence of arterial catheters, pulmonary artery pressure significantly increased.

5. Cardiogram

Angiography; Pulmonary angiography can be found through the arterial catheter into the aorta and can show aortic constriction. Retrograde aortic angiography showed ascending aorta and arch dysplasia or constriction or disconnection of the aorta. Left atrial angiography can understand the development status of the mitral valve.

Diagnosis of left heart dysplasia

Make a diagnosis based on clinical manifestations and related tests.

Left Heart Dysplasia Treatment

Medical treatment: Digoxin strong heart can be applied, continuous intravenous drip of prostaglandin E delays the closure of the arterial catheter; oxygen inhalation and increased pulmonary blood flow can improve the oxygen saturation of the arterial system. Arterial blood oxygen saturation maintained at 35-45mmHg can effectively take into account the patency of the arterial catheter and the coronary blood supply. But medical treatment is not a long-term effective treatment.

Surgical treatment:

Now I mainly do Norwood surgery, mainly in three stages.

(1) The main pulmonary artery is separated from the left and right pulmonary arteries, and merged with the dysplastic ascending aorta, so that the right ventricle circulates through this pipe supply system. Under the condition that the left and right ventricles of the atrial septum are kept open, the source of pulmonary blood is passed Blalock-Taussig surgical supply of body-lung shunt.

(2) Hemi-Fontan surgery, that is, two-way Glenn surgery, is performed at about 6 months after birth to connect the superior vena cava to the pulmonary artery.

(3) Perform Fontan surgery or total vena cava pulmonary anastomosis within 12 to 18 months after birth to make the right atrium and right pulmonary artery anastomosis or use an external tube to connect the inferior vena cava to the right pulmonary artery.

Pulmonary artery pressure determines the success of the operation. Approximately 1/2 of the cases can be treated with physiological correction to obtain satisfactory results, but the right ventricle has been subjected to systemic circulation pressure for a long time, and its long-term effect remains to be followed up. Heart transplant is an effective radical operation.

Prognosis of left heart dysplasia

The average age of non-operative patients is 4 to 5 days, but most of them die within 48 hours after birth. Late arterial catheter closure may survive for weeks or even months. Surgical treatment is the only life-saving measure. Follow-up analysis of the improved prognosis of Fontan surgery showed that the survival rate of Norwood's first-stage operation has reached 75% and the one-year survival rate of 58% after third-stage operation. However, not all patients after Norwood's first-stage surgery can enter Fontan surgery, but need to choose a heart transplant.