Noninvasive Mapping (IMAGE) Washington University School of Medicine Caption A noninvasive cardiac map shows the electrical signals of a single beat. The gray area is a scar from a prior heart attack. The electrical signals that cause ventricular tachycardia enter the scar at the blue area, follow the yellow arrow along the border of the scar and exit the scar at the red area. Credit Philip Cuculich Usage Restrictions None 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.