Over an eight-year period, echocardiograms were transmitted by ISDN at 384 kbit/s for a total of 132 patients suspected of having congenital heart disease (CHD). Five transmitted scans were inadequate. Hands-on echocardiograms were performed subsequently on 116 of the remaining 127 cases (91%). Major CHD was diagnosed in 42 of the 116 infants (36%) and minor CHD in 49 (42%). The telemedicine diagnosis was accurate in 97% of the cases (kappa = 0.90). There were four diagnostic errors. Transfer to the regional unit was avoided in 95 patients (72%). The present study shows that high diagnostic accuracy is possible using a telemedicine link to transmit images obtained with the assistance of real-time guidance by a paediatric cardiologist. The results also demonstrate the importance of an expert interpreting the echocardiographic images, since the accuracy of diagnosis was considerably improved (the kappa coefficient increased from 0.14 to 0.90).