Echocardiograms provided the basis for complete diagnoses of the following conditions: (1) idiopathic hypertrophic subaortic stenosis in five patients in the absence of typical physical findings; (2) left atrial myxoma in two patients with clinical features of mitral stenosis, and right atrial myxoma in a patient with a heart murmur (one of a total of five); (3) right ventricular volume overload in three patients with atrial septal defect and one patient with tricuspid regurgitation; (4) combined mitral and aortic valve disease in three patients. In five other patients with mitral stenosis unsuspected aortic stenosis was demonstrated. Echocardiography is a valuable aid in cardiac diagnosis. (JAMA 230:873-876, 1974)