The clinical symptoms, laboratory findings, apexcardiograms, phonocardiograms and echocardiographic features are related to hemodynamic and angiocardiographic measurements in 9 patients with atrial myxoma (6 left atrial and 3 right atrial tumors). Emphasis is placed on the clinical clues to the diagnosis. Echocardiography has become the most useful non-invasive method of investigation. However, angiocardiography remains the definitive diagnostic procedure.