Patients with leadless cardiac pacemakers (LCPs) may encounter fewer short- and mid-term complications than patients with transvenous pacemakers (TVPs), according to a head-to-head comparison published in Heart Rhythm. LCPs, however, are more likely to cause pericardial effusion—an uncommon but frightening complication.

“LCPs represent a new paradigm in cardiac pacing developed to mitigate complications by eliminating the need for a subcutaneous pocket and transvenous leads,” wrote lead author, Daniel J. Cantillon, MD, Cleveland Clinic, Cleveland, Ohio. To boot, these devices, which were FDA approved in 2016, are about 10 times smaller than TVPs, self-contained, sans wires, and placed transfemorally.

Previous research has shed light on the short-term safety and efficacy of LCPs at 6 months,, Complications arose in 4.0%-6.7% of patients, with cardiac perforation being the most common. In comparison, complications occurred in as many as 12.0% of patients receiving TVPs, and were related to implantation, an interventional approach that has endured ever since the TVP’s inception.

With regard to LCP studies, the investigators wrote that “while the quantity and type of complications were fewer and different from those reported with TVPs, comparison is limited by differences in patient comorbidities and study characteristics.”

In the current study, Dr. Cantillon and colleagues aimed to fill these gaps in previous research by comparing short- and mid-term complications of LCPs (Abbott’s Nanostim LCP) with conventional single-chamber TVPs (from any manufacturer) by using extended follow-up data from the previously published LEADLESS II IDE study and a propensity-matched control cohort, respectively.

Of note, LEADLESS II is a prospective, nonrandomized, multicenter clinical study conducted in the United States, Canada, and Australia in patients with indications for permanent single-chamber ventricular pacing who received the Nanostim LCP between 2014 and 2016. Data for the TVP comparison came from a large, US insurance database.

The investigators categorized complications, including infection (eg, endocarditis), thoracic trauma (eg, pneumothorax and hemothorax), pocket complication (eg, hematoma and pocket revision), electrode dislodgment, other lead complication needing revision, venous embolism or thrombosis, cardiac perforation plus down-stream sequelae, and generator complications (including explants).

“To avoid overestimating complication rates, multiple codes from the same complication category that occurred on the same or consecutive dates were counted as a single event,” the researchers wrote.

Short-term complications happened within 1 month of implantation; whereas, mid-term complications happened between 1 and 18 months of implantation.

“The overall reduction in both short- and mid-term events was driven by a virtual elimination of lead, pocket, and infectious complications, suggesting that this disruptive technology has successfully targeted the most common sources of traditional pacemaker complications observed over the past 50 years,” the researchers wrote.

“The data from this study [are] encouraging, and we expect complications from leadless pacemakers to continue to decline as the technology improves and physicians gain experience implanting these devices,” Dr. Cantillon said. “While this research shows benefit for leadless pacing, we must keep in mind that the field is still too young to compare the long-term results of this technology, the implications of which will not be fully understood for at least another decade.”

This study was funded by Abbott.

This story is contributed by Naveed Saleh and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.