Anomalous origin of the left coronary artery from the pulmonary trunk is a rare congenital heart defect. Cardiac catheterization remains the standard means of diagnosis. Our purpose in this study is to emphasize the importance of assessing the electrocardiogram when making the diagnosis, in addition to taking note of transthoracic echocardiographic findings. We also analyzed the sensitivity of each parameter under investigation.

Between June, 1999, and March, 2007, we studied 9 patients, 6 males and 3 females, with a mean age of 3.02 years, in whom anomalous origin of the left coronary artery from the pulmonary trunk was suspected subsequent to transthoracic echocardiographic examination. We examined their electrocardiograms, and undertook cardiac catheterization. In all patients, the transthoracic echocardiogram had shown retrograde flow into the pulmonary trunk, with the left coronary artery arising from pulmonary trunk, along with a dilated right coronary artery, or intercoronary collateral vessels. In 8 patients, the electrocardiogram showed deep Q wave in leads I and aVL, with depression of the ST segments over lead V4 through 6, or inversion of the T waves in leads I, II, and aVL. In the remaining patient, the electrocardiogram showed incomplete right bundle branch block. Later, cardiac catheterization confirmed the diagnosis in 8 patients, but the other patient was shown to have the right coronary artery arising from the pulmonary trunk.

By combining transthoracic echocardiography with study of the electrocardiogram, it is possible to provide accurate evaluation of anomalous origin of the left coronary artery from the pulmonary trunk.