Medtronic's tiny cardiac monitor shows improved afib detection in real-world study

Medtronic's Reveal Linq wireless cardiac monitoring implant--Courtesy of Medtronic

Two years ago, Medtronic ($MDT) rolled out its Reveal Linq, a tiny implantable cardiac monitor, with annual sales predictions to the tune of $1 billion to $2 billion. Now, the company is reporting one-year data from a real-world study of the device showing that it was better at detecting atrial fibrillation than previously thought.

The device, a cardiac monitor one-third the size of an AAA battery and implanted in the upper left side of the chest, is one-tenth the size of its predecessor, the Reveal cardiac monitor. It transmits data wirelessly to a patient bedside monitor and its battery life allows it to monitor abnormal heart rhythms for up to three years.

The study involved 1,247 patients in the U.S. who had cryptogenic stroke, or stroke of unknown origin. It sought to examine the incidence and duration of afib events in these patients during one year of follow-up. At the one-year mark, the device detected 1,737 afib episodes in 192 patients, a detection rate of 16.3%, Medtronic said in a statement. This is a 32% relative increase compared with the device's one-year detection rate measured in a randomized, controlled clinical study. The company previously reported data at 182 days.

Having a stroke raises a person's risk for a second stroke. According to the National Stroke Association, recurrent stroke accounts for one in four of the nearly 800,000 strokes suffered by Americans each year. Current guidelines recommend 30 days of cardiac monitoring within 6 months of a cryptogenic stroke. But Medtronic's data suggest that 72% of the patients in the study would have gone undiagnosed if their monitoring had been limited to 30 days, raising questions about the current standards.

"[T]he vast majority of patients had their first AF episode beyond the range of 30-day conventional monitoring, reinforcing the need to reevaluate the standard AF monitoring guidelines for cryptogenic stroke patients," said co-author Dr. John Rogers, a cardiologist at the Scripps Clinic in La Jolla, CA, in the statement.

In a push to expand its reach, last May, Medtronic launched a study to evaluate physician office insertion of the Reveal Linq. The device can help physicians identify when to pursue other stroke prevention measures, including the adoption of other Medtronic products. "Over the three to three and a half year life of a Reveal Linq, roughly 20% of those patients will be identified as being appropriate candidates for device therapy," said Medtronic Cardiac & Vascular Group President Mike Coyle on a February 2015 earnings call. One of these products is the tiny pacemaker Micra, which won FDA premarket approval this month.

- here's the statement