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The New User-Friendly Pacemaker

June 17, 1986|PATRICK MOTT | Mott lives in Santa Ana. and

Roland Sarrazen thought he was going crazy.

He had been a martial arts instructor for nearly 18 years, had taught judo, aikido and karate, had been physically sharp and well conditioned.

Then, over a period of time, and without any discomfort or pain, Sarrazen began to find that he was unable to perform relatively simple physical tasks. He couldn't teach martial arts. He couldn't exercise. He became easily fatigued and lethargic.

After nearly six years of not knowing what was wrong, he had a severe attack of cardiac arrhythmia--irregular heartbeat--and was told that his condition was terminal. During the attack, he said, his heart was beating at rates too fast for the muscle to pump blood. With the next serious attack, he was told, he would likely die.

Sarrazen believes he was saved in 1979 by the implantation in his chest of an artificial heart pacemaker, which maintained his heartbeat at a uniform 70 beats per minute. But within the next five years he began to suffer from a phenomenon known as "pacemaker syndrome," in which the patient, in spite of the uniform heartbeat, becomes progressively fatigued. Sarrazen began to feel himself slipping once again.

Today, however, the 48-year-old Sarrazen swims, hikes, even jogs a bit--activities made possible by an experimental pacemaker he received in 1984 that automatically adjusts the wearer's heart rate in response to physical activity.

Nearly all other pacemakers available today in the United States are designed to be fixed at a uniform number of beats per minute, usually 70. They maintain that rate whether the wearer is running a marathon or sitting in a chair.

The new device, called Activitrax, is the first single-lead-wire, rate-responsive pacemaker to become commercially available in the United States, according to its developers, the Minneapolis-based company Medtronic Inc. It received official marketing approval from the federal Food and Drug Administration on Thursday.

Electrical Impulses

Usually implanted in the upper chest between layers of fat and muscle tissue, the rate-responsive pacemaker is attached to a wire threaded through veins into one of the upper chambers of the heart and delivers electrical impulses that stimulate contractions of the heart muscle at rates between 60 and 150 beats per minute.

It will sell for about $4,800, a few hundred dollars more than a fixed-rate pacemaker.

According to cardiologists who helped test it, the Activitrax is a breakthrough for pacemaker wearers who have diseased upper heart chambers because the only other rate-responsive pacemaker available in the United States relies for its function upon healthy upper chambers. (That pacemaker uses dual leads, one of which senses the healthy heart rhythm from the upper chambers and transmits corresponding impulses through the second lead to the malfunctioning lower chambers.)

The new pacemaker weighs about 1 1/2 ounces and is a little larger than a silver dollar. Inside is a tiny forest of microcircuits and a minute, flexible crystal that emits electrical impulses in response to pressure from body motion.

All but Back to Normal

"With my first pacemaker I could get around, I could do minimal things--about 30% or 40% of normal activity for a person my age," said Sarrazen, who lives in Buena Park. "Since getting the new one, though, I'm able to do maybe 80 to 90% of the activity I was able to do in the past.

"The doctor is telling me that I'll have a totally normal life span."

Sarrazen's doctor is John Messenger, chief of the coronary care unit at Memorial Hospital in Long Beach and an associate professor of medicine at UC Irvine Medical Center in Orange. Messenger, a cardiologist, was a chief clinical investigator during the development of Activitrax and implanted the device in 15 Southern California patients--one of whom was Sarrazen--during the 3 1/2-year experimental period.

"Our philosophy is that a patient should be as close to normal as possible," Messenger said. "With the fixed-rate pacemakers, we were saving people from dying but they weren't functionally active. With Roland, we wanted to turn him back into a semi-jock."

The idea of a rate-responsive pacemaker is not new, and there have been a handful of attempts at perfecting one using various methods in the last five years, Messenger said. But success has been limited, said Ken Anderson, a research engineer at Medtronic and the inventor of Activitrax.

'Just Sat Around'

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