Tiny pacemaker could revolutionize cardiac care

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Although he's quick to tell you he almost never gets sick, Dr. Raul Sierra's role is reversing and he is the patient.  

After attending medical school in Cuba, he came to the U.S. and trained at Cook County Hospital in Chicago before relocating to Tampa. Since then, he spent more than 40 years practicing family medicine in the same hospital where he is now a patient

Four years ago, at the age of 92, he retired due to a heart condition.

"Not because he's my husband, but he was a wonderful physician, wonderful father, wonderful husband, grandfather and now great grandfather. He loved his patients," wife Martha, standing at his bedside, said.

Martha said Dr. Sierra’s heart rate drops so low, his blood pressure falls, and his brain doesn't get enough blood. That has caused him to fall several times.

Two of those falls resulted in bone fractures, one in his lower leg, and the other in his hip. 
"He had one a couple of months after he retired and had hip surgery. It has been very scary moments," she recalled.

Most recently, he fell at their church.  

"He's actually needed a device for the past five years, his heart rate is in the forties," cardiologist Dr. Kevin Makati, who specializes in heart rhythm problems, explained. 

Today, Dr. Sierra is becoming the second patient at St. Josephs' Hospital Tampa to get a tiny pacemaker called Micra TPS, made by Medtronic.

"It is the smallest pacemaker in the world,” Dr. Makati explained while holding the tiny device in the palm of his hand. 

Traditional pacemakers use wires surgically placed in the heart. A disc-shaped implant usually rests beneath the skin on the chest wall. Micra TPS requires no surgery or wires; it’s placed directly in the heart through a vein in the leg in a cardiac catheterization lab.

"This is why this device is so exciting, because it allows us access to patients that might not be able to tolerate traditional surgery," Makati explained.

Using a fluoroscopic x-ray image, Dr. Makati showed the device inside Dr. Sierra’s heart.

"We deliver it to the end of the heart and it just so happens that the heart has a network of muscle fibers that it gets lodged in. Once it's in there, it's not coming out," Dr. Makati explained.

Doctors place a wand-like device on top of the chest, helping Micra TPS establish two-way communication with a laptop computer. Both programming and diagnostics - like monitoring and setting heart rate - are accessible wirelessly. 

For Dr. Sierra, the pacemaker is set to send impulses to his heat whenever its pace drops too low. 

"The device actually has some smartness in it, so it will accelerate his heart rate to whatever he is doing; it's a very sophisticated device," Dr. Makati said. 

Another advantage to the high tech pacemaker is it can be monitored from home, 24/7.

"There's a console we send with the patient that sits right next to the bed," Dr. Makati said.
Micra TPS is only able to be used in one chamber of the heart, the right ventricle. Studies and approval are ongoing for multi-chamber use. The battery is made to last 12 years. If any device malfunctions, because it's so tiny, doctors may implant a second one right next to it. 

According to the FDA website, in a clinical trial of 719 patients, 98-percent had adequate heart pacing. Complications occurred in fewer than 7-percent of participants and included prolonged hospitalizations, blood clots in the legs and lungs, heart injury, device dislocation and heart attacks.