New implantable heart monitor shares data with patient's smartphone

John Bottko doesn't want to have a heart defibrillator implanted in his chest — he doesn't want the pain of surgery, and he definitely doesn't want to jeopardize the commercial driver's license he needs for his job, which would happen if he had a defibrillator put in.

But neither does Bottko want to go into sudden cardiac arrest without having a defibrillator inside him that can kick in automatically if he needs it.

The 31-year-old Coon Rapids resident may be at increased risk for having his blood stop flowing because of inherited hypertrophic cardiomyopathy. It's also possible that he's not at increased risk — doctors have told him different things, and past testing has proved inconclusive.

So Bottko had a small heart monitor called the Confirm Rx, made by Abbott Laboratories, implanted to give him and his doctor a snapshot of his heart activity at the push of a button on his phone for at least two years.

"I'm so borderline, there's not necessarily a reason to do it, unless we find something on the heart monitor," Bottko said, discussing whether to have an implantable defibrillator placed. "We'll know before the end of these couple of years."

Last week, Bottko became the first person in Minnesota outside a trial to get Abbott's new implantable heart monitor, which is placed just below the skin in the chest using an injector device in a clinic. The device was cleared for commercial sales by the Food and Drug Administration in late October.

The heart monitor is about the size of a large paper clip, and its battery is certified to last at least two years. The device has the words "St. Jude Medical" emblazoned on the front because that was the Minnesota-based company that pioneered the original Confirm device back in 2008, as well as this model. Illinois-based Abbott Labs acquired St. Jude Medical and its line of heart devices in January.

Dr. Jason Garlie, the electrophysiologist at the Metropolitan Heart and Vascular Institute in Coon Rapids who implanted Bottko's cardiac monitor, said hypertrophic cardiomyopathy patients may be good candidates for implantable monitors because the condition creates risks for blood-flow problems unevenly.

Such patients may be at risk for having ventricular arrhythmias, which can prevent oxygen-rich blood from reaching the brain and potentially result in cardiac arrest.

"People with hypertrophic cardiomyopathy live normal life spans, but there still is a sub-segment, a small sliver of patients, who are at higher risk of sudden cardiac arrest. And so our job is to try to discern who is at risk so that we can protect them," Garlie said. "This tool is an excellent way to help him let us know when, or if, (Bottko) does have any ventricular arrhythmias."

Abbott doesn't make the only insertable cardiac monitor on the market.

Medtronic says it introduced the world's first implantable cardiac monitor, called the Reveal, in 1998, and then 16 years later it introduced the world's smallest monitor, the Reveal Linq, which is about one-third the size of a AAA battery. Earlier this year the FDA cleared a version of the Linq that has "TruRhythm Detection" programming, which reduces false bradycardia and cardiac pause readings compared to earlier versions of the device.

Consumers can buy an Apple Watch that comes embedded with four optical heart-rate sensors that are currently being tested in a 500,000-person clinical trial to see how well the device can detect signs of atrial fibrillation, a heartbeat disorder that affects the heart's upper chambers. The FDA has also approved two electrocardiogram devices made by AliveCor that work with Apple products to take medically accurate ECG readings.

For now, though, Abbott said the Confirm Rx is the only insertable cardiac monitor designed to be compatible with a smartphone to detect cardiac arrhythmias. Abbott said the device continuously monitors a person's heartbeat to detect a range of cardiac arrhythmias, including irregular heartbeats, or atrial fibrillation.

The Confirm Rx includes cyber security measures to deter hackers who might be interested in its wireless signals. The implanted monitor encrypts wireless communications using 128-bit encryption, and creates a unique 128-bit key for a paired device that is verified at the onset of each new communication. The smartphone app that receives and sends data uses a security protocol called TLS, plus another layer of cryptographic protection called SHA 256.

Metropolitan Vascular's Garlie said the device provides a far more accurate assessment of cardiac risk than traditional methods, and thus will help better pinpoint patients who may or may not need more significant interventions, like defibrillators, which carry risks including infection and inappropriate shocks.

"As electrophysiologists, we are very mindful about this," he said. "And we want to treat the patients that need to be treated and reassure the patients that don't need to be treated."