Partial left anomalous pulmonary venous return: a diagnostic dilemma

Two adults were seen with left partial anomalous pulmonary venous return with intact atrial septum. Both cases had remained undiagnosed despite medical attention since childhood, including previous cardiac catheterization in one patient. Noninvasive tests, indocyanine green dye injections, pulmonary artery angiography, and venous sampling for oximetry high in the superior vena cava above the entry of the innominate vein will help establish the diagnosis of this disorder.