Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High-energy clamp simplifies heart surgery for atrial fibrillation

12.10.2006
Heart surgeons at Washington University School of Medicine in St. Louis have helped usher in a new era in the surgical treatment of atrial fibrillation. Using radiofrequency devices -- rather than a scalpel -- they've greatly shortened the surgery and made it significantly easier to perform.

"Because of the devices, the procedure -- called the Cox-Maze procedure -- has gone from an operation that hardly anyone was doing to one that 80 to 90 percent of U.S. heart surgeons are now performing," says Ralph J. Damiano Jr., M.D., the John Shoenberg Professor of Surgery and chief of cardiac surgery at the School of Medicine and a cardiac surgeon at Barnes-Jewish Hospital.

Adults older than 40 have a 25 percent risk of eventually developing atrial fibrillation in which the upper chambers of the heart twitch rapidly instead of contracting fully and regularly. The condition can lead to stroke or heart failure.

For some patients, medications can control the abnormal heart rhythms and the risk of clotting associated with atrial fibrillation, but they do not cure the disorder. The Cox-Maze procedure has a greater than 90 percent cure rate.

Damiano and his colleagues have played a vital role in the development and testing of radiofrequency devices for treating atrial fibrillation. The devices deliver high-energy radiofrequency waves to heart tissue and very quickly create scars or ablations, which replace most of the complex incisions required by the Cox-Maze procedure. The ablations disrupt the atria's abnormal electrical activity and normalize heart rhythm.

The research team found that surgeons needed to apply the devices for only a few seconds at a time to get effective ablation of the atrial wall, and the devices caused no injury to surrounding tissue. The time needed for the procedure went from more than 90 minutes to about 30 minutes.

The modified Cox-Maze procedure eliminated atrial fibrillation in over 90 percent of patients in a recent study, a number that compares favorably to the outcomes of the traditional cut-and-sew procedure. About three-quarters of patients treated no longer need drugs to prevent abnormal heart rhythms or excessive blood clotting, Damiano says.

The Cox-Maze procedure is named for James Cox, M.D., former director of Washington University's division of cardiothoracic surgery, who led the St. Louis research group that developed the procedure in 1987. The procedure -- which revolutionized treatment of atrial fibrillation -- calls for ten precisely placed incisions in the upper chambers of the heart. The incisions are then sewn up and eventually form scars in the atrial tissue.

The scar tissue stops atrial fibrillation by interfering with chaotic electrical signals that cause the atria to contract irregularly. By placing roadblocks in the way of these misplaced electrical impulses, the Cox-Maze procedure redirects them down their normal route so that they stimulate regular heartbeats.

The clamp-like jaws of the radiofrequency ablation devices latch onto a section of heart muscle and deliver a thin, focused line of energy that heats and ablates the tissue. Ablation with the devices can replace all but two small incisions that would typically be made during a traditional Cox-Maze procedure.

"We've not only reduced the time needed for the procedure, we've made the procedure easier to perform," Damiano says. "In addition to eliminating most of the incisions, the radiofrequency ablation clamp removes the potential for error by monitoring when the lesion goes all the way through the tissue and automatically shutting the power off at that point."

By simplifying the Cox-Maze surgery, the method will make the procedure available to more patients. "This has made it possible to offer this curative operation to almost everyone coming for heart surgery who has chronic atrial fibrillation," Damiano says.

Other devices exist to create the Cox-Maze lesions -- these use microwaves, lasers, ultrasound or freezing. Damiano believes that the type of device used at the School of Medicine is superior because other types of devices may not be as consistent or as fast and can cause collateral damage to other areas of the heart.

Damiano and colleagues are now working to develop a device that will make the Cox-Maze procedure even less invasive. The device would allow surgeons to perform the procedure on the beating heart and do away with the need to stop the heart and place the patient on a heart-lung machine. Heart-lung machines can introduce the potential for stroke or organ failure with extended use.

"We've made the first big step: we've taken a very complicated operation and made it simpler. We've tremendously decreased morbidity and virtually eliminated mortality," Damiano says. "Now we are aggressively working on a device that would allow us to do the full set of Cox-Maze lesions without using a heart-lung machine."

Gwen Ericson | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht Tracking movement of immune cells identifies key first steps in inflammatory arthritis
23.01.2017 | Massachusetts General Hospital

nachricht Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>