Expectant mom gets heart help with 3-D mapping

August 30, 2016 Providence Health Team

This article originally appeared in Heart Beat magazine, Providence Sacred Heart Medical Center.

Amanda Buckles’ heart wouldn’t stop racing. She woke up at 6 a.m. on Feb. 14, 2016, with an elevated heart rate, and by 11 a.m. it hadn’t returned to normal. Buckles called her midwife. Go to the emergency department, her midwife advised.

At the ED, Buckles was given medications to slow her heart. Nothing seemed to work at first, but by around midnight the medical team was able to normalize the heart rate. Fortunately, Buckles’ unborn baby—her fourth child—wasn’t affected. Still, Buckles found it unsettling. After many years without any problems, her heart was racing every day, sometimes several times. She was concerned about her baby’s health, as well as her own.

Triggering trouble

Buckles was born with supraventricular tachycardia, or SVT, a condition that causes the heart to beat rapidly or erratically. Rogue electrical signals between the heart’s upper and lower chambers fire abnormally in a sort of short circuit, interfering with normal electrical signals coming from the sinoatrial node, the heart’s natural pacemaker. A rapid heartbeat brought on by exercise, stress or hormonal changes may last a few minutes to several days, potentially reducing blood supply to the body.

As a child, Buckles frequently experienced lightheadedness and fatigue. Even jumping up and down would cause her heart to race. Buckles took medication to help manage the condition. “My heart has always had a mind of its own,” she says.

Ready for resolution

The visit to the emergency department scared Buckles. After discussing the options with her physician, she decided to have an ablation procedure, her second. An ablation is a minimally invasive technique to correct abnormal heartbeats, also known as arrhythmia. The first attempt on Buckles was unsuccessful.

Enter Mark Harwood, M.D., cardiologist at Providence Spokane Cardiology, and Chris Anderson, M.D., pediatric cardiologist at Providence Center for Congenital Heart Disease. (Both clinics are members of Providence Spokane Heart Institute.) The doctors are also cardiac electrophysiologists, meaning they specialize in diagnosing and treating heart rhythm disorders. They use 3-D mapping to perform ablations, which is what Dr. Harwood recommended for Buckles because of her pregnancy. Although ablation procedures typically use both 3-D mapping and fluoroscopy, or X-ray technology, it was too dangerous to expose Buckles’ fetus to X-ray radiation, so doctors would perform the 3-D mapping alone.

“I knew I was in good hands,” Buckles says. “And it was exciting to contemplate a normal heart rate and lifestyle.”

Finding and fixing the problem

One month after her visit to the emergency department, Buckles checked in for her procedure. She was placed under general anesthesia, and then the medical team inserted a catheter with a miniature electromagnetic sensor in the tip into her femoral vein and guided it to her heart. Electrodes were placed on her upper body and a magnet attached under the table to create a magnetic field. As the catheter moved within the field, it sent signals to a computer, much the same way a GPS system maps streets. On screen, the signals morphed into a 3-D model of Buckles’ heart.

Alongside a team that included an obstetrician to monitor Buckles’ unborn baby, an anesthesiologist, technicians and nurses, Drs. Harwood and Anderson worked in tandem, one at the bedside navigating the catheter, the other in the control room tracking the virtual catheter on screen.

Locating the area in her heart that was triggering the arrhythmias was not easy, however. The accessory pathway, a grouping of cells creating the short circuit and causing the SVT, was in an abnormal, small, pouchlike vein in the back of the heart called a diverticulum. “Mapping the anatomy of the coronary sinus where the diverticulum was discovered was very difficult,” Dr. Anderson says.

Eventually, they were able to reach the accessory pathway in the diverticulum and destroy it using a short blast of heat in the form of radio-frequency current from the catheter. The procedure took nearly five hours; catheter ablations typically take less than two hours.

The success of the procedure without fluoroscopy buoyed the doctors’ belief that 3-D mapping could one day replace X-rays altogether. “We know it can be done,” Dr. Harwood says.

Buckles’ unborn baby was unfazed by the ordeal. In fact, Buckles gave birth to a healthy girl on May 31. She had a home birth, which wouldn’t have been possible before the surgery.

Since the ablation, Buckles hasn’t had one episode. “I feel like a new woman with a new heart,” she says.

Does your heart race or beat erratically at times? Talk to your health care provider to find out more. You can find a Providence provider in your area by clicking here.

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