Ultrafast computer tomography (CT) is one of the major new imaging modalities that has become available for the evaluation of patients with heart disease. With cine CT it is possible to obtain high resolution images of the heart at 58-ms intervals. The inplane resolution is 0.7 to 1.5 mm, and the slice thickness is 3 to 9 mm. Images require the intravenous injection of nonionic contrast agents to obtain quantitative information about cardiac function. Cine CT has thus far been used in 3 general areas that relate to the evaluation of patients with heart disease: evaluation of cardiac structure and function, evaluation of vein bypass graft patency and flow reserve, and measurements of regional myocardial perfusion. Because of the outstanding spatial resolution of the images, it is possible to obtain very precise information about cardiac structure and function. The weight of the left ventricle and right ventricular walls can be measured to +/- 5%, and the stroke volumes and end-diastolic volumes of all 4 cardiac chambers can also be measured with an accuracy of +/- 5%. With this technology it is possible to determine the magnitude of aortic regurgitation within +/- 5 to 8%. This modality has also proved useful in the diagnosis of surgically resectable left ventricular aneurysm and a multitude of other cardiac disorders that involve abnormalities in cardiac structure, including congenital heart defects, aortic aneurysms and constrictive pericarditis. These diagnostic procedures use the peripheral injection of usually about 100 ml of contrast media and can ordinarily be completed in less than 15 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)