University of Maryland researchers link 3-D CT scans to standard ablation techniques

Researchers at the University of Maryland School of Medicine in Baltimore have developed a novel 3-D imaging approach that may improve the accuracy of treatment for ventricular tachycardia, a potentially life-threatening heart rhythm disorder that causes the heart to beat too fast. The new approach couples CT (computed tomography) images with conventional ablation techniques to eliminate erratic electrical circuits in the heart that produce arrhythmias. The results of a feasibility study have been published online in Circulation: Arrhythmia and Electrophysiology, a journal of the American Heart Association.

Electrical signals control how frequently the heart beats and how the heart muscle contracts to move blood through the body. Following a heart attack, irregularly shaped sections of dead scar tissue may form in the heart and block the electrical flow or cause a short circuit. The researchers say a growing number of people who have survived severe heart attacks go on to face a weak, erratic heartbeat, and that has prompted the search for more effective ways to treat these electrical disturbances.

Current ablation procedures, which use high-energy radio waves to treat certain types of serious arrhythmias, have only 50-60 percent long-term success. The research team theorized that with the aid of sophisticated 3-D CT imaging, treatment may be more precise and take less time.

According to the study's senior author, Timm-Michael L. Dickfeld, M.D., Ph.D., associate professor of medicine at the University of Maryland School of Medicine, "We can use 3-D CT imaging to guide us more rapidly to areas of the heart that may cause the electrical abnormalities responsible for ventricular tachycardia, and move away from parts of the heart that do not contribute to the abnormalities." Dr. Dickfeld is a cardiologist at the University of Maryland Medical Center and chief of electrophysiology at the Baltimore VA Medical Center.

A CT scanner, which takes multiple X-ray images in a matter of seconds as it rapidly spirals around the body, yields three significant types of information about the heart; abnormal cardiac anatomy, blood flow and heart muscle contraction. After two years of testing and customizing software, the research team has succeeded in combining all of these factors into a three-dimensional imaging format that can work accurately with existing equipment in an electrophysiology laboratory, where ablation procedures are performed.

This project builds on the team's earlier work that studied how well a combination of PET (positron emission tomography) and CT technology would provide advanced imaging. Study co-author Jean Jeudy, M.D., a radiologist at the University of Maryland Medical Center and assistant professor of diagnostic radiology and nuclear medicine at the University of Maryland School of Medicine, says information from imaging technologies such as CT and PET has been used independently, up till now. "Each modality has advantages in imaging, but our idea is to pool their strengths to create a synergism that results in the best and safest therapies for patients."