A 2-month-old boy presented to the former emergency department with a
fever of 38 ° C and hypoxemia and respiratory failure. He was
transferred to our hospital on suspicion of myocarditis because he had
an enlarged chest X-ray, a 30% EF, a decrease in left heart function,
and an increase in myocardial deviation enzyme(CK-MB 149.8 IU/L,
TnT-1(+)). Echocardiography revealed dilation and poor contraction of
left ventricle and no abnormalities in the origin of the coronary
arteries (Figure1A, B), and treatment with cardiac stimulants,
antibiotics, and IVIG was started for myocarditis. After that, his
cardiac function did not improve, and contrast-enhanced CT was taken on
day 12. He was diagnosed with anomalous origin of the left coronary
artery from the pulmonary artery (ALCAPA). The LCA diverged from the
right PA instead of the main PA (Figure1C). Coronary transplantation was
performed on day 13. The postoperative course was uneventful, and he was
transferred to our hospital on the 21st day after the operation.
ALCAPA mostly originates from the left posterior sinus at the root of
the PA, which can lead to coronary steal syndrome and myocardial
ischemia, and the incidence of the disease is approximately 1/3,00,000,
accounting for 0.25% to 0.5% of congenital heart disease(1, 2). In
this case, the LCA diverged from the right PA instead of the main PA,
which is extremely rare and has never been reported before. This
difference in bifurcation might make the diagnosis of ALCAPA on
echocardiography more difficult.
ALCAPA should be considered in the differential diagnosis of
myocarditis, and contrast-enhanced CT or catheterization should be
considered even if coronary
artery abnormalities are not detected on echocardiography.