Engineered Tissue Pacemaker Substitute (IMAGE) Boston Children's Hospital Caption Engineered tissue provides an electrical connection between the atria (not shown) and the ventricles (at left). Cardiac cells appear in red and green, and the implanted cells in green alone. Credit Courtesy Douglas Cowan, Ph.D., Children's Hospital Boston Usage Restrictions Please use the credit line indicated. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.