RHYTHMS Promising new therapy offers more effective treatment of atrial fibrillation

HAYWIRE

Electrophysiologists use technology to eliminate abnormal heart rhythms

Driving home from work one day last fall, Clarence Rodefeld’s heart started beating out of control and he blacked out. He had a head-on collision, totaled his truck and broke three ribs. He was lucky it wasn’t worse.

BY ERIN FAIRCHILD

Rodefeld knew what was happening. For 12 years, he suffered from a dangerous heart condition called atrial fibrillation.

“It’s scary. You don’t know if you’re about to have a heart attack. You can feel your heart pounding out of your chest, and you know it’s critical. It can kill you,” Rodefeld said.

Approximately 2.2 million Americans live with atrial fibrillation, a condition that causes the heart to beat erratically, potentially causing heart attack or stroke.

“When people have atrial fibrillation, their hearts have regular bouts of erratic, fast beating,” said Dr. Miguel Valderrabano, director, division of cardiac electrophysiology at the Methodist DeBakey Heart Center. “They often have an uncomfortable awareness of their heartbeat. Sometimes they have chest pain. They get weak. They can show up with no symptoms at all or with more extreme complications such as stroke or heart failure.”

“It feels like you’re not in this world,” said Rodefeld, a 61-year-old warehouse manager. “It’s like you’re not a normal human being. It zaps all the energy out of you.”

“The medical quandary around atrial fibrillation is its erratic behavior, which makes it challenging to treat,” said Dr. Nadim Nasir Jr., cardiologist and electrophysiologist at the Methodist DeBakey Heart Center. “Tiny electrical impulses continually run through a healthy person’s heart, giving it the impetus to beat and pump lifesustaining blood through the body. When these electrical impulses go haywire, atrial fibrillation occurs.”

Anti-arrhythmic medications can help slow do but medications tend to work on

Rodefeld controlled his atrial fibrillation with medication for years, but there came a point when the medications weren’t enough. He had episodes of erratic heartbeats on a daily basis. There even came a time when he had to take two months of short-term disability from his job because of the condition. In and out of the hospital, he was sapped of energy and felt awful physically.

“My family knew that it changed me as a person. All I wanted to do was sit around and feel bad,” he said. “I was scared. It’s a frightening feeling to have your heart beat uncontrollably.”

Anti-arrhythmic medications such as sotalol, flecainide, propafenone and amiodarone can help slow down the heart rate and regulate heart rhythm associated with atrial fibrillation, but medications tend to work only 40 to 60 percent of the time.

As patients age, the medications don’t work as well. In addition, many of these medications have significant side effects including lung, skin and eye toxicity. Some can even lead to sudden cardiac death when used in diseased hearts.

If the condition can not be controlled with medication, electrophysiologists — physicians who specialize in the diagnosis and treatment of abnormal heart rhythms — mechanically and permanently interrupt the errant electrical impulses.

They accomplish this with ablation — a promising new therapy for more effective treatment of atrial fibrillation. The procedure allows them to identify the errant circuits and eliminate them by inserting a minimally invasive catheter through the groin veins into the heart and delivering heat or cold to the affected areas.

If atrial fibrillation is allowed to go unchecked, blood pools in the atria, the top chambers of the heart, and clots can form. If a clot dislodges, it can cause a stroke. About 15 percent of strokes are caused by atrial fibrillation.

“Atrial fibrillation is a moving target. The electrical impulses change continually. The electrical activity of the heart, and more specificallythe left atrium, is quite complex. Consequently, mapping of these signals in an effort to target areas of ablation can be time consuming,” said Nasir, who is the medical director of the cardiac electrophysiology laboratory and director of clinical electrophysiology services at the DeBakey Heart Center.

Dr. Miguel Valderrabano

own the heart rate and regulate heart rhythm, nly 40 to 60 percent of the time.

Erratic heartbeats often begin at the point where the pulmonary vein enters the heart. One option is to treat the tissue surrounding the pulmonary vein entrance in the left atrium, electrically isolating the vein and stopping the errant electrical impulses.

Another option is to identify and ablate areas where the heart tissue is beating faster. These areas can trigger irregular heartbeats. A last option is to ablate where the nerves of the heart are.

There is great variation among patients in how the electrical currents operate. One of the greatest challenges for electrophysiologists is to better understand this variability in order to better personalize treatment.

Rodefeld was referred to Valderrabano for ablation. Valderrabano ran a three-dimensional CT image of Rodefeld’s heart before the procedure to help visualize the anatomy and currents in his heart. He then used the CT image during the procedure so that he could compare Rodefeld’s “live” heart to the one recorded on the CT scan.

With the technology available at Methodist, Valderrabano used the reconstructed 3D image of the heart and the real-time image of the catheter going into Rodefeld’s heart for more precise accuracy in the placement of the ablation energy treatment.

Valderrabano also used 3D magnet-guided navigation to manipulate the catheter remotely into the exact locations he wanted to ablate the errant tissue. This robotic system allows for manipulation of the catheter via magnetic fields that direct it to desired locations, speeding up the procedure and minimizing complications.

He also used intracardiac echocardiography, a technology that enables a physician to see the heart and vessels from the inside of the heart. He located the area near Rodefeld’s pulmonary vein and used radiofrequency energy to perform the ablation that short-circuited the errant currents and eliminated the irregular heartbeats.

“I feel tremendous,” Rodefeld said after his ablation. He advises people with uncontrolled atrial fibrillation to see a doctor because they can give patients comfort and control.

“I feel like I’m 40 again. I’ve got my body, my attitude and my charm. It’s all back,” he said.

Dr. Nadim Nasir Jr.

To obtain a physician referral, call 713.790.3333 or visit www.methodisthealth.com.