Double Outlet Left Ventricle

Double-outlet left ventricle (DOLV) is an extremely rare congenital cardiac malformation in which both the aorta and the pulmonary artery arise, either exclusively or predominantly, from the morphologic left ventricle.

Epidemiology

Prevalence is unknown. The birth prevalence is estimated at less than 1/ 200,000 live births.

Clinical description

DOLV usually manifests during the neonatal period with cyanosis, tachypnea, exertional dyspnea, failure to thrive, sweating (especially during feeding), unresponsiveness and/or fatigue. DOLV occurs most commonly in the form of atrial situs solitus with atrioventricular (AV) concordance but is often associated with cardiac anomalies such as a ventricular septal defect (VSD), an atrial septal defect, pulmonary stenosis, right ventricular hypoplasia, patent ductus arteriosus, and tricuspid atresia (see these terms). The clinical manifestations depend largely on the type of the associated cardiac defects, e.g. pulmonary or aortic outflow tract obstruction resulting from pulmonary or aortic valve stenosis respectively. DOLV is classified into two sub-types depending on the location of the VSD and the position of the great arteries: DOLV with normal great arteries (DOLV NGA type) with subpulmonary or doubly committed subarterial VSD and levo-position of the anterior pulmonary artery; and DOLV with transposition of the great arteries (DOLV TGA type) with subaortic or doubly committed subarterial VSD and levoposition of the anterior aorta. The two sub-types are almost clinically indistinguishable, apart from cyanosis being more prominent in TGA type.

Etiology

The etiopathology is not clearly understood. Embryologically, DOLV could result from excessive leftward shift of the embryonic conotruncus, anomalous differential absorption of sub-pulmonic and sub-aortic conus, or anomalous differential conal growth.

Diagnostic methods

Diagnosis is based on 2-D echocardiography combined with magnetic resonance imaging (MRI) showing both great arteries arising from the morphologic left ventricle. Chest X-ray and/or cardiac catheterization can also be performed.

Differential diagnosis

Differential diagnosis includes transposition of the great arteries and double outlet right ventricle (see these terms).

Antenatal diagnosis

Prenatal echocardiographic diagnosis is possible but very difficult.

Genetic counseling

DOLV is a sporadic disease.

Management and treatment

Biventricular repair is the usual treatment for DOLV and is usually accomplished by an intraventricular baffle procedure, by the Rastelli procedure or by a variant of the Lecompte operation. Pulmonary root translocation from the left to the right ventricle can also be performed and provides excellent anatomic and hemodynamic repair. When other cardiac malformations are present, other techniques can be used such as Fontan-type cavopulmonary derivation in the presence of right ventricular hypoplasia.

Prognosis

DOLV is associated with high mortality, generally due to heart failure, myocardial infarction or aortic thrombosis. With surgery, the five-year survival rate is estimated at 70-75%. Most patients will continue to present with residual cardiac anomalies, such as aortic or mitral valve regurgitation, arrhythmias or hypertension.