Agitated saline contrast studies (bubble studies) can be performed with either transthoracic or transesophageal echocardiography for the detection of right-to-left atrial shunts. The echocardiograms of 94 consecutive patients who underwent saline contrast studies with transthoracic and transesophageal approaches were reviewed to compare the ability of these modalities to detect right-to-left atrial shunts.