Imagine a device that continuously records your heart’s activity. Imagine that device has been surgically implanted in your chest. Now imagine the size of the scar from that implant surgery.
Unless you have some personal experience with the Reveal LINQ Insertable Cardiac Monitor, your imagination is probably wrong. The device is smaller than a AAA battery. The cut used to allow insertion under the skin can be covered by a Band-Aid.
A few months ago, Providence Hospitals proudly announced it was the first in the state to implant the devices. The Medical University of South Carolina Medical Center announced a few days later that it was using the device. Dorn VA Medical Center implanted its first LINQ a few weeks later.
Palmetto Health boasted late last year of a 95-year-old patient being among the first locally to get transcatheter aortic valve replacement, a surgery technique that precludes opening the chest cavity. Providence has been doing the procedure for about year, and Lexington Medical Center will begin using the surgical procedure this spring.
New heart technology and surgery procedures quickly become almost commonplace, but that doesn’t make them any less remarkable.
‘Just a little nick’
Dr. Manish Jain and Dr. Venkateshwar Gottipaty are electrophysiologists at South Carolina Heart Center who perform the LINQ procedures at Providence. The device is the new generation version of loop recorder technology that has been around for decades. Loop recorders keep track of heartbeat changes 24 hours a day, since rhythm problems don’t usually occur in a doctor’s office.
“A lot of people have (heart rhythm problems), but it’s so elusive,” Jain said. “They’ll notice a shortage of breath for five minutes, but by the time they’re in the hospital, it’s over.”
Early loop recorders were much larger and involved wires outside the body, and the first ones recorded only for a couple of days at a time. Patients couldn’t take showers while hooked up to the earliest versions.
Later versions could be implanted under the skin, but they still were as large as the palm of a hand. The surgery required a large incision and general anesthesia in an operating room.
“This has changed the ball game because you can do it anywhere,” Jain said of the LINQ. “It requires just a little nick and local anesthetic.”
The incision size has shrunk from 2 or 3 centimeters to 3 millimeters, Jain said. Meanwhile, the monitoring capabilities are even greater with the small device. Doctors set up the parameters they want to measure, depending on the patient’s symptoms. If the heartbeat is too high or too low, the device records it.
When the patient arrives at the hospital or the physician’s office, a paired handset downloads the recordings from the implanted device. The results help indicate whether the patient’s symptoms are related to heart rhythm problems.
The new technology also can turn the implanted device into a pager that sends a notice to physicians if a patient has abnormal heart rhythms. With these sorts of new medical devices, electrophysiology labs are a fascinating place to work these days.
“The technology is improving, and we’re helping a lot of folks,” Jain said.
Implanted devices that monitor heart activity and, when necessary, provide life-saving shocks have been around for 20 to 25 years. The long-standing technology, however, involved inserting wires through the circulatory system with electrical leads actually implanted in the heart tissue. The wires were attached to a monitor tucked under the skin that triggered shocks through the wires when a heart beat dangerously out of rhythm.
“The problem related to that is it’s inside the heart and it’s a foreign body,” said Dr. Sony Jacob, director of cardiac arrhythmia services at Dorn. “It can bring in infection, and it can trigger fibrous tissue formation, scar tissue formation.”
And when those wires create problems, removing them is difficult and dangerous. In some cases, the problems can be deadly.
The newest version of the technology keeps the wires and the electrical leads outside the circulatory system. Jacob recently began using such a device — the Boston Scientific Subcutaneous Implantable Cardioverter Defibrillator.
The plastic monitor of the device — about the size of a standard Reese’s Cup — is implanted under the skin on the side of the rib cage. The wires loop down below the heart and then up to the sternum area in a tunnel under the skin but above the rib cage.
“We’re not going into the heart at all,” Jacob said.
Two leads on the wire and one in the monitor serve the function of an electrocardiogram, constantly measuring heart rhythm. The end of the wire and the monitor also serve as the two poles for the electrical shock to reset the heart’s rhythm if the EKG notices problems.
The device is programmed to distinguish between normal and abnormal rhythm. Any time the rhythm goes up or down quickly, “it’s alerted … It says yes, it is abnormal. Shock it,” Jacob said.
Abnormal rhythms such as ventricular fibrillation or ventricular tachycardia can be deadly. “You get a rhythm and in three to four seconds, you don’t get blood supply to the brain, you’re down on the ground,” Jacob said. “In those patients, if their rhythm is not converted back to normal they will die.”
In the first generation of these internal defibrillators, the monitors were so large the only place they would fit was in the abdomen. Then they grew smaller. Now they don’t even have to touch the heart.
There is one major hurdle in the new device.
“When you implant this, you don’t know whether it works,” Jacob said. “So what we do is we create a bad rhythm. We literally make the patient die and bring him back.”
For that reason, the new device isn’t ideal for all patients. But the new technology’s limitations are shrinking quickly.
Jacob stretched the boundaries in one of his first uses of the device. A paralyzed diaphragm had forced the patient’s heart to the right-center of the chest. Using the standard implant method, the heart wouldn’t have been directly between the two electrical leads. Jacob had to implant the monitor on the patient’s back with the lead going deeper under the skin to the right side of the sternum instead of the left.
“People were very skeptical about it, but I was very convinced because scientifically it should work,” Jacob said. “This is how science evolves. If you just stick to what’s in the books, science will never evolve.”
Less invasive methods
Sometimes new technology is as much about delivery methods as it is about mechanical devices. Dr. Matthew Cantrell at Palmetto Heart last year began offering transcatheter aortic valve replacement, a variation that’s done without opening the chest.
In the past, repairing damaged or diseased valves involved opening up the chest cavity to cut out the old valve and replace it with a new one – either donor tissue or a mechanical valve. Such a major invasive operation could be more dangerous than the leaky valve itself, especially on elderly or sick patients. That’s where TAVR comes in.
“We don’t have to crack the chest,” Cantrell said. “We are able to deliver it through the vascular system inside the old valve and deploy it.”
They use the TAVR sheath and delivery system to slip the new valve through the vascular system starting with an incision in the groin or between two ribs and into the damaged heart valve. The new valve tissue pushes the old valve tissue outward and takes over the job of moving blood through the heart.
Cantrell performed TAVR surgery on 95-year-old Grace Norris of West Columbia. Norris had a pacemaker installed in 2007, but heart disease later narrowed her aortic valve opening to the point where she had difficulty moving around her house without fatigue or shortness of breath.
One week after her TAVR surgery, Norris returned to the clinic with the use of a walker. If she had undergone standard open chest valve replacement, she likely would have been bedridden at home for a week or two.
TAVR surgery has been used in Europe for nearly a decade and has been in trial stages in the U.S. It was approved by U.S. regulators last year, and Palmetto Heart has done four of the surgeries in recent months.
As with any new technology or procedure, it is expensive. For now, insurance only covers the procedure for very sick or elderly patients who likely wouldn’t survive the more invasive, open chest valve replacement surgery. But that could change, just as so much about heart procedures has evolved.
“A lot of what was done surgically 20 years ago is done through catheters now,” Cantrell said.
Physicians also can plug a hole between the chambers of the heart through catheters. The device used in the procedure — the Amplatzer Septal Occluder — was first approved by regulators in 2001, and it’s still amazing to consider.
What’s commonly referred to as a hole in the heart — technically an atrial septal defect — is a congenital condition that can lead to shortness of breath, arrhythmia, an enlarged heart or heart failure. The defect used to be closed using sutures or a patch during open heart surgery. Now, some holes can be closed with only a small incision in the groin area for a catheter, said Dr. Robert Leonardi of Lexington Cardiology, who performs the surgery at Lexington Medical Center.
The Amplatzer Septal Occluder, made by St. Jude Medical, includes a delivery sheath that can be pushed through a catheter and blood vessels into the heart. But it’s what’s inside the sheath that’s fascinating — two flexible nickel alloy mesh disks.
“You can grab it in the middle and pull to make it one long piece that goes into the sheath,” Leonardi said.
The surgeon, using a version of ultrasound technology called intracardiac echocardiolography to see inside the heart, manipulates the sheath into the heart and through the hole between chambers. By pulling back slightly on the sheath, one of the disks is unfurled on one side of the hole, and then the other disk is unfurled on the other side.
The two disks together “sort of make a sandwich,” Leonardi said.
The mesh not only blocks the hole, but it encourages the growth of tissue. As the tissue spreads, it covers the disks, which become part of the wall between the chambers of the heart.
Much like the TAVR surgery, the ASO surgery allows quicker recovery time because it doesn’t require opening the chest.