MUSC 2nd in country to offer new high-tech heart mapping

May 10, 2018
Monitor showing heart
Cardiac cartography: Technology shows doctors where heart problems are and helps them come up with simpler solutions than in the past. Photos by Emma Vought

MUSC Health has become the first hospital in South Carolina and the second in the United States to use a new, high-tech catheter called the HD Grid to give doctors more insight into the mechanisms of heart rhythm problems. A catheter in this context is a long tube that’s threaded through blood vessels into the heart.

Surgeon Jeffrey Winterfield, director of the Ventricular Arrhythmia Service at MUSC Health, called the use of the new catheter the latest advance for a team that’s becoming a go-to center for complex arrhythmia management.

“The HD Grid is a significant evolutionary step forward in catheter design for ultra-high-density mapping of cardiac surfaces to gain novel insights,” Winterfield said. “Previously understood mechanisms of arrhythmias may have oversimplified circuits of these fast heart beats. Using this technology, we have gained a much richer and more detailed sense of how to localize circuits, which may result in shorter and safer procedures.”

Winterfield is not being paid by the company that makes the device to talk about or use it.

So far, the MUSC Health team has used the technology on five patients. “The outcomes exceeded our expectations,” Winterfield said. “We shaved off about two hours from procedure times for complex ventricular tachycardia cases.”

In a person who has ventricular tachycardia, abnormal electrical signals cause the heart to beat more quickly than normal. It can run the gamut from mild, with no symptoms, to dangerous, causing the heart to stop.

Winterfield said the new catheter is similar in design to other high-density catheters but has an important difference. “It has multiple spines, each with four small electrodes evenly spaced from each other. These small and tightly spaced electrodes create a very small and sensitive antenna to detect abnormal electrical activity in scarred up or diseased areas of the heart.”

Dr. Jeffrey Winterfield
Dr. Jeffrey Winterfield is able to see on a monitor what the catheter is finding in a patient's heart.

Older catheters would be limited to just two electrodes that are larger and more widely spaced, Winterfield said. “The result of the old arrangement would be that we would see only the larger signals and miss the rich and detailed circuits in the very diseased areas of the heart.”

While cardiac catheterization does carry some risks including bleeding, heart attack and stroke, it rarely causes major complications.

Winterfield said a collaborator at the University of Chicago, Roderick Tung, was the first in the U.S. to use the new technology with a patient. “We did the second. We have been passionate about understanding arrhythmia mechanisms, and, starting several years ago, we began exploring novel approaches to high density mapping to better understand and treat irregular heart rhythms — especially ventricular tachycardia.”

He said the impact of the mapping device will be substantial. “It may make treatment of complex arrhythmias more straightforward and accessible. Ventricular tachycardia ablations are notoriously complex and lengthy, and we need better approaches to make these procedures safer and more feasible in less specialized centers.

“Dr. Tung and I will be commencing a clinical trial using ultra high-density mapping methods with this HD Grid catheter in an effort to reduce procedure times and to improve outcomes of VT ablation.”

Ablation involves using radiofrequency to destroy small areas of the heart responsible for causing irregular heartbeats.