Originally created 07/23/98

Calming a racing heart



Wallace McCullough never figured he was miswired.

"I had no idea what was going on," said the retired, 72-year-old mechanical contractor. "It was awful. Every now and then my heart would start running away. This would happen in the middle of the night and wake you slap dab right up."

Doctors were able to control his racing heart -- called tachycardia -- with medication, but it didn't make him feel much better.

"I was a zombie, to tell you the truth," Mr. McCullough said. Though he had retired to a 20-acre spread in Harlem with a pond and acres of vegetable gardens, he couldn't seem to enjoy it.

"It would scare the hound out of you" when the attacks still came, Mr. McCullough said. "When something like this happens, you sit in that chair and think, `Well, old boy, it's time for the Good Lord to take you.' "

Then Mr. McCullough was referred to cardiologist David Clark for a revolutionary procedure called catheter cardiac ablation, which seeks to correct a problem in the electrical system that controls the beating of the heart.

In a normal heart, a small node in the right atrium, or upper right chamber, sends out an electrical signal that causes the upper chambers to contract and push blood into the lower chambers, or ventricles. That initial signal passes through another small node on the edge of the two chambers, the atrioventricular node, which slows and regulates the timing of the signal before passing it on. Once the signal reaches the ventricles, they contract, and the whole process starts all over again. This accounts for the "lub-dub" sound of the heartbeat, Dr. Clark said, and ensures a smooth, regular flow of blood in and out of the heart.

But in some people, there is an extra piece of muscle fiber near the AV node that acts as a bypass for the signal and in effect creates a circle, or short-circuit, for the signal to return too quickly and causes the heart to beat more rapidly.

In years past, the only hope was medication or, failing that, open-heart surgery to remove the offending piece of muscle fiber, Dr. Clark said. Patients faced not only the risk of major surgery but a week's recovery in the hospital, Dr. Clark said.

Contrast that with the scene on a recent Wednesday morning, when Dr. Clark and his staff prepared a 67-year-old Sandersville, Ga., woman for cardiac ablation. The woman was awake, lying under blue drapes on a table beneath a fluoroscope, which provides a constant X-ray image. Thin black loops of wires sprouted from her upper right thigh. On the screen, the snaky black lines of three catheters could be seen already inside her heart, having been passed up through a vein in her leg and one in her neck. At the end of each catheter were carefully spaced electrodes. Using a stimulant drug, Dr. Clark prepared to begin the electrophysiology study, in which he would stimulate a controlled attack in order to pinpoint the precise spot of the extra fiber. Sitting in front of two computer monitors, Dr. Clark studied a screen of blue, green and yellow lines -- denoting the signals from the catheters -- as registered cardiovascular technician Robin Johnson flipped switches and turned dials, sending an electrical charge through first one electrode, then another. On the screen, first the blue line and then the green went from long, slow waves into a thick high squiggle. Back and forth, from one electrode to another, Dr. Clark attempted to narrow down the exact spot where the attack could be stimulated, the area he needed to eliminate.

He turned back toward the table.

"What's her heart rate over there?"

Reyhan Clark, another registered cardiovascular technician, glanced up at the heart monitor.

"230," she said.

"Good gosh," Dr. Clark said, turning back around and fiddling once more with the lines on the screen.

After nearly an hour, he returned to the operating table, where soft snores emanated from the patient. He quickly threaded in a new thin wire through the leg, this one with a tip that could deliver a burst of radio-frequency energy.

Carefully watching the monitor, where the muscle of the heart was actually not visible, he slowly, carefully threaded the catheter toward its target with tiny twists and flicks of his fingers. He gauged his spot in relation to where the other carefully positioned catheters were.

"It's a game of millimeters," he said later.

"Let's do it at 30 watts for 60 seconds," he said. He let off a short burst, then another. The catheter would burn a small section of the heart muscle right up against the base of the AV node, "about the size of the tip of my little finger," he said. The scarred tissue, which can't carry an electrical signal, would thus prevent a short-circuit.

Then he stood back, eyes on the computer monitor of multi-colored waves, as the staff tried to stimulate another tachycardia attack. After about 20 minutes, he stepped back from the table.

"Let's call the family, tell them she's done. I'll be out to speak to them in a few minutes," Dr. Clark said.

It was 9:23 a.m., less than 90 minutes from the start of the procedure. By afternoon, the woman would be on her way home.

And most likely, completely cured, Dr. Clark said. She is the 75th patient to undergo the procedure since Dr. Clark arrived in August to start the program. None has had a relapse. The first, Mr. McCullough, still can't believe it.

"It's a miracle," he said. And it's actually cheaper for the insurance companies, Dr. Clark said.

"The cost of the procedure is actually recouped within two years," Dr. Clark said, because the patients now avoid taking drugs the rest of their lives, as well as trips to the emergency room. "From a financial standpoint, it's one of the most cost-effective things we do."

But the difference for Mr. McCullough is more than money. It is life itself.

"Beforehand, I had no interest in anything," he said. "I was scared to go anywhere. I was scared to go out of town. I was scared to leave the doctors."

Now, he's looking forward to gardening (if the weather allows) and new trips.

"I'm going to the Ozarks fishing," he said. "It's just energized me."