Transmission of full-length echocardiographic images over ISDN for diagnosing congenital heart disease

Objectives: To study the feasibility of transmitting full-length diagnostic-quality echocardiograms with video conferencing systems linked by ISDN. Methods: Forty-three previously video-recorded full-length echocardiograms (22 complete two-dimensional Doppler studies, 21 separate M- mode studies) were transmitted from a site 30 miles distant using desktop video conferencing systems linked with one ISDN line (128 kbps). Blinded interpretations of the original recorded and transmitted studies were made by two pediatric cardiologists (two-dimensional Doppler) and a pediatric sonographer (M-mode). Results: Diagnoses of normal (N = 12) and abnormal (N = 10) conditions were made from the original tapes; the same interpretations were made from the transmitted studies. Twenty-one specific abnormalities in the 10 abnormal studies were seen on both original and transmitted videotapes. These abnormalities ranged from simple congenital heart defects, including ventricular septal defect, atrial septal defect, and patent ductus arteriosus, to complex ones, such as coronary artery fistula, double-outlet right ventricle, and complete atrioventricular canal. Qualitatively, there was mild degradation in gray scale, brightness, and contrast of the images. Six M-mode variables from the transmitted images had excellent concordance with the original tracings (P = 0.506 to 0.838; r = 0.86 to 0.97). Conclusions: Although our sample size was small, this preliminary experience indicates that video conferencing equipment utilizing ISDN technology is a reliable method for transmitting full-length diagnostic-quality echocardiographic studies from remote sites. This technology may have a significant impact on the management of pediatric patients with suspected heart disease. Further evaluation is warranted.