The value and limitations of phonocardiography, systolic time intervals, apex cardiography and kinetocardiography in the diagnosis of impaired cardiac function during rest and haemodynamic stress were critically reviewed on the basis of studies carried out in our laboratory, as well as reports in the literature. When compared with invasively-obtained measurements, none of the above-mentioned techniques allows the prediction of heart function quantitatively in a single given patient. However, when one considers the broad overlap of mechanocardiographic measurements in normal subjects and patients with heart disease and defines an abnormal mechanocardiogram accordingly, these methods may be used to diagnose abnormal cardiac function with adequate specificity though low sensitivity.