Radionuclide angiocardiography in the clinical evaluation of cardiac malpositions in situs solitus in adults.

A right-sided position of the heart in the chest in situs solitus is an abnormal feature easily discernible from a plain chest radiograph. This cardiac malposition may be due to cardiac displacement (dextroposition), which is usually a feature of lung disease, or a structural abnormality of the heart (dextrocardia). Because each condition has different clinical pathologic implications, it is important to distinguish them. Chest films, however, often provide no conclusive information. We performed radionuclide angiocardiography (RNA) in six adults with a cardiac malposition in situs solitus. It was found that morphologic data obtained from the serial images may distinguish dextroposition from dextrocardia. In addition, these images permitted us to diagnose congenitally corrected transposition, a cardiac anomaly which occurs with increased frequency in situs solitus with dextrocardia. Quantitative shunt detection performed during this procedure is helpful in the differential diagnosis of dextroposition and able to distinguish uncomplicated dextrocardia from dextrocardia associated with other cardiac abnormalities. RNA therefore is a valuable and easily performed method in the analysis of cardiac malpositions in adults.