• Abnormal septation of the conotruncus into aorta and pulmonary artery.
• Persistence of the pulmonary buds and involution of the aortic buds that will eventually form the coronary arteries.

• Left ventricle is perfused with desaturated blood.
• Collateral flow tends to steal blood from the myocardial blood vessels into the pulmonary artery, resulting in myocardial ischemia.

• Rare anomaly
• 87% of patients with this anomaly present in infancy

• Cardiomyopathy
• Mitral-valve incompetence
• Left ventricular failure from other causes
• Colic
• Bronchiolitis

• Intractable congestive heart failure
• Paroxysms of poor feeding, pallor, and sweats
• Irritability
• Sometimes asymptomatic
• Occasionally may be symptomatic in infancy and then gradually improve (with adequate coronary collateralization)
• Older children and adults may have dyspnea, syncope, or angina pectoris on effort
• Sudden death

• Signs of congestive heart failure
• Loud P2 component of S2
• Gallop rhythm
• Murmur: mitral incompetence or a continuous murmur reminiscent of a coronary arteriovenous fistula
• Diagnosis should be entertained in any infant presenting with cardiomegaly or perplexing cardiorespiratory symptoms.

Test: Chest x-ray study
Significance: Cardiomegaly, pulmonary edema

Test: Nuclear imaging
Significance: Thallium myocardial perfusion imaging shows reduced uptake in ischemic regions.

Test: Electrocardiography
Significance: Anterolateral infarct pattern in an infant (Q in I, aVL, V4–V6), abnormal R wave progression in precordial leads

Test: Echocardiogram
Significance: Attachment of coronary artery to pulmonary artery by two-dimensional Doppler interrogation shows flow passing from coronary artery to great artery rather than vice versa.

• Large right coronary artery
• Function and wall-motion abnormalities of left ventricle
• Echogenic papillary muscles
• Mitral regurgitation
• Cardiac catheterization
• Low cardiac output
• High filling pressures
• Pulmonary hypertension
• Aortic root angiography shows passage of contrast medium from left coronary to pulmonary artery

Test: Pulmonary artery angiogram
Significance: Shows reflux of contrast medium into the left coronary artery.

• Ligation of origin of left coronary artery and reconstitution of flow with saphenous or internal mammary graft.
• Direct reimplantation of the left coronary (with a button of pulmonary artery around the origin) into the aorta.
• Creation of an aortopulmonary window and tunnel that directs blood from aorta to the left coronary ostium (Takeuchi procedure).
• Ligation of the origin of the left coronary artery to prevent steal in very sick infants

• Untreated, 65% to 85% die before the age of 1 year, usually after 2 months of age (when pulmonary vascular resistance falls).
• Few improve spontaneously.
• Late results after surgery are fairly good.
• Mitral-valve incompetence may progress in spite of surgery and its repair may be required later.

Emmanouilides GC, Riemenschneider TA, Allen HD, Gutgesell, HP, eds. Moss and Adams’ heart disease in infants, children and adolescents including the fetus and young adult, 5th ed. Baltimore: Williams & Wilkins, 1995:776–780.

Fyler C. Nadas’ pediatric cardiology. Philadelphia: Henley & Belfins, St. Louis: Mosby, 1992;51:715–718.