A new small, wireless self-contained pacemaker appears safe and feasible for use in patients, according to a new study published by researchers from Icahn School of Medicine at Mount Sinai on March 24 in the American Heart Association journal Circulation.
Those complications can stem from the pulse generator implanted under the skin of the chest, where infections or skin breakdown can occur, and particularly from the leads, or wires, that run from the generator through a vein to the heart. Leads can break, dislodge or contribute to a vein blockage.
However, the new pacemaker has no leads — its pulse generator lies within the unit in the heart – and is placed without the need for surgery.
At 6 millimeters in diameter and about 42 millimeters long, the wireless device is smaller than a triple-A battery. It's faster and easier to implant than traditional pacemakers, Dr. Reddy says, and it's programmed and monitored similarly.
"While a much larger study is required to prove this, one may expect the leadless pacemaker to be associated with less chance of infection and lead-related problems such as lead fracture," says Dr. Reddy. "Overall, the self-contained pacemaker is a paradigm shift in cardiac pacing."
The study, called LEADLESS, was conducted in 33 Caucasian patients, average age 77, two-thirds men, at two hospitals in Prague and one in Amsterdam. The self-contained pacemaker was successfully implanted in 32 patients, or 97 percent. Ninety-four percent were free of complications through the three-month study period, the researchers reported.
The new device is a self-modulating pacer guided into place using a catheter inserted in the femoral vein and is affixed to the heart in the right ventricle, the same place a standard lead would be located. The device is for patients who require single-chamber pacing, or roughly 20 percent to 30 percent of United States and European patients who need pacemakers. Patients who need dual-chamber pacing would still require traditional pacemakers, according to Dr. Reddy.
Among the study's 33 patients, one suffered complications during the procedure and underwent emergency surgery but later died after suffering a stroke.
After three months, the new pacemakers were functioning well, the researchers found. They are continuing to track the patients and expect to report longer-term outcomes later this year. Meanwhile, a much larger study at multiple U.S. locations that will include longer-term follow-up is under way, says Dr. Reddy.
In February, Dr. Reddy launched the LEADLESS II clinical research trial after implanting the United States' first leadless pacemaker at The Mount Sinai Hospital. LEADLESS II is planning to enroll 670 patients at 50 centers across the U.S., Canada, and Europe.
The co-authors of the newly published LEADLESS study findings include: Reinoud E. Knops, MD; Johannes Sperzel, MD; Marc A. Miller, MD; Jan Petru, MD; Jaroslav Simon, MD; Lucie Sediva, MD; Joris R. de Groot, MD, PhD; Fleur V.Y. Tjong, MD; Peter Jacobson, BS; Alan Ostrosff, MS; Srinivas R. Dukkipati, MS; Jacob S. Koruth, MD; Arthur A.M. Wilde, MD, PhD; Josef Kautzner, MD, PhD; and Petr Neuzil, MD, PhD.
The study was funded by St. Jude Medical, the manufacturer of the Nanostim pacemaker.
Dr. Reddy receives financial compensation as a consultant and advisory board member for St. Jude Medical, the study sponsor and manufacturer of the Nanostim pacemaker system being evaluated in this study. In addition, in 2013 he received one-time financial compensation from St. Jude Medical in the form of an option buyout relating to St. Jude Medical's acquisition of Nanostim.
About the Mount Sinai Health System The Mount Sinai Health System is an integrated health system committed to providing distinguished care, conducting transformative research, and advancing biomedical education. Structured around seven member hospital campuses and a single medical school, the Health System has an extensive ambulatory network and a range of inpatient and outpatient services—from community-based facilities to tertiary and quaternary care.
The System includes approximately 6,600 primary and specialty care physicians, 12-minority-owned free-standing ambulatory surgery centers, over 45 ambulatory practices throughout the five boroughs of New York City, Westchester, and Long Island, as well as 31 affiliated community health centers. Physicians are affiliated with the Icahn School of Medicine at Mount Sinai, which is ranked among the top 20 medical schools both in National Institutes of Health funding and by U.S. News & World Report.