At North Mississippi Medical Center, Dr. Karl Crossen, a Tupelo cardiologist who specializes in the heart’s electrical system, developed a procedure to treat hypertrophic obstructive cardiomyopathy, a genetic disease where the heart’s septum – the muscle between the heart’s pumping chambers – is enlarged or thickened. It can cause shortness of breathe, chest pain, dizziness, fainting and heart failure.
“It’s associated with sudden death,” Crossen said. “It creates a problem with the heart muscles that causes some type of electrical instability.”
The primary treatments are open heart surgery to remove a portion of the muscle and a less invasive treatment done in the cath lab where alcohol is injected into a blood vessel in the septum to kill a portion of the muscle. Patients who go through the alcohol procedure often need a pacemaker in conjunction with it.
Crossen developed a radiofrequency septal ablation technique using an advanced cardiac mapping system – which was designed to find “short circuits” in the heart and guide treatment to exactly the right spot. The cardiac mapping system also allows the physician to see exactly where the septum is located and how thick it is.
“We pick an area we want to take out based on the thickest part of the muscle,” Crossen said. A special radiofrequency catheter is used to burn the muscle away. It’s all performed with needle punctures of the leg vessels, similar to the way cardiac catheterization is performed.
Usually trials for procedures and devices are done by medical device manufacturers. It’s unusual to see such a study initiated by a physican.
“That doesn’t happen every day,” said Marsha Jones, clinical research manager for Cardiology Associates, who worked with Crossen closely to organize the study.
It took two years to develop the study protocol, working closely with the NMMC Institutional Review Board, which oversees all research studies conducted at the hospital.
“There’s no question it was a much better protocol by the time it went to the FDA,” thanks to the feedback from the review board, Crossen said.
Biotronik, a worldwide medical technology company specializing in the development of pacemakers, ICDs, stents, and ablation equipment, agreed to fund the trial; because the procedure is experimental, it isn’t covered by medical insurance.
In July, they submitted the protocols to the FDA, and in November, Crossen received permission to use the procedure on up to 12 patients. They’ve done two patients so far as part of the study, and have a third scheduled.
Gene Ward of Thaxton was the first patient in the study, and had previously gone through the alcohol procedure only to have his septum grow back. Since having the radiofrequency septal ablation, tests show his septum has shrunk and he’s noticed he doesn’t get fatigued as easily.
After the study’s 12 cases have been completed and follow up data has been gathered, Crossen and Jones plan to go back the FDA to ask for the trial to be expanded to more centers and more cases with the continuing oversight from the NMMC review board. Colleagues of Crossen’s at University of Richmond and the University of Mississippi are already interested.
“The goal is to show it works at least as well as alcohol septal ablation,” Crossen said.