Chiari network is an embryonic remnant of the right sinus venosus. It appears as a thin, fenestrated membrane attached to two or more regions within the right atrium. Usually, a Chiari network has a benign course; however, rare complications associated with a Chiari network have been reported. We present the case of a neonate with hypoxemia and a Chiari network protruding into the right ventricular inflow tract associated with right-to-left shunting across the patent foramen ovale throughout the cardiac cycle. We noted spontaneous improvement after 3 weeks of life.
Keywords: Chiari network; Cyanosis; Eustachian valve; Hypoxemia; Sinus venosus.