Esophageal echocardiography has been developed for use in patients with chronic obstructive pulmonary disease and is a safe diagnostic procedure which provides high resolution mirror image echoes of many cardiac structures. Conventional anterior and esophageal echocardiograms were performed in 38 subjects. Esophageal echoes were of diagnostic quality in all 38 subjects, anterior echoes were of diagnostic quality in only 18. Measurements from anterior and esophageal echocardiograms correlated well for aortic valve diameter (r = 0.87), left atrium diameter (r = 0.96), mitral valve EF slope (r = 0.97) and less well for aortic root diameter (r = 0.69).